Phenoxymethyl heterocyclic compounds

ABSTRACT

Phenoxymethyl compounds that inhibit at least one phosphodiesterase 10 are described as are pharmaceutical compositions containing such compounds an methods for treating various CNS disorders by administering such compounds to a patient in need thereof.

PRIORITY

This application is a continuation of U.S. patent application Ser. No. 13/722,595, filed Dec. 20, 2012, entitled “Phenoxymethyl Heterocyclic Compounds,” which is a divisional application of U.S. patent application Ser. No. 12/642,026, filed Dec. 18, 2009, now U.S. Pat. No. 8,343,973, entitled “Phenoxymethyl Heterocyclic Compounds,” which claims the benefit of priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/176,413, filed May 7, 2009, entitled “Vicinal Substituted Heterocyclic Compounds.” The entire contents of these priority applications are incorporated herein by reference.

BACKGROUND

Cyclic phosphodiesterases are intracellular enzymes which, through the hydrolysis of cyclic nucleotides cAMP and cGMP, regulate the levels of these mono phosphate nucleotides which serve as second messengers in the signaling cascade of G-protein coupled receptors. In neurons, PDEs also play a role in the regulation of downstream cGMP and cAMP dependent kinases which phosphorylate proteins involved in the regulation of synaptic transmission and homeostasis. To date, eleven different PDE families have been identified which are encoded by 21 genes. The PDEs contain a variable N-terminal regulatory domain and a highly conserved C-terminal catalytic domain and differ in their substrate specificity, expression and localization in cellular and tissue compartments, including the CNS.

The discovery of a new PDE family, PDE10, was reported simultaneously by three groups in 1999 (Soderling et al. “Isolation and characterization of a dual-substrate phosphodiesterase gene family: PDE10A” Proc. Natl Sci. 1999, 96, 7071-7076; Loughney et al. “Isolation and characterization of PDE10A, a novel human 3′,5′-cyclic nucleotide phosphodiesterase” Gene 1999, 234, 109-117; Fujishige et al. “Cloning and characterization of a novel human phosphodiesterase that hydrolyzes both cAMP and cGMP (PDE10A)” J. Biol. Chem. 1999, 274, 18438-18445). The human PDE10 sequence is highly homologous to both the rat and mouse variants with 95% amino acid identity overall, and 98% identity conserved in the catalytic region.

PDE10 is primarily expressed in the brain (caudate nucleus and putamen) and is highly localized in the medium spiny neurons of the striatum, which is one of the principal inputs to the basal ganglia. This localization of PDE10 has led to speculation that it may influence the dopaminergic and glutamatergic pathways both which play roles in the pathology of various psychotic and neurodegenerative disorders.

PDE10 hydrolyzes both cAMP (K_(m)=0.05 uM) and cGMP (K_(m)=3 uM) (Soderling et al. “Isolation and Characterization of a dual-substrate phosphodiesterase gene family: PDE10.” Proc. Natl Sci. USA 1999, 96(12), 7071-7076). In addition, PDE10 has a five-fold greater V_(max) for cGMP than for cAMP and these in vitro kinetic data have lead to the speculation that PDE10 may act as a cAMP-inhibited cGMP phosphodiesterase in vivo (Soderling and Beavo “Regulation of cAMP and cGMP signaling: New phosphodiesterases and new functions,” Curr. Opin. Cell Biol., 2000, 12, 174-179).

PDE10 is also one of five phosphodiesterase members to contain a tandem GAF domain at their N-terminus. It is differentiated by the fact that the other GAF containing PDEs (PDE2, 5, 6, and 11) bind cGMP while recent data points to the tight binding of cAMP to the GAF domain of PDE10 (Handa et al. “Crystal structure of the GAF-B domain from human phosphodiesterase 10A complexed with its ligand, cAMP” J. Biol. Chem. 2008, May 13^(th), ePub).

PDE10 inhibitors have been disclosed for the treatment of a variety of neurological and psychiatric disorders including Parkinson's disease, schizophrenia, Huntington's disease, delusional disorders, drug-induced psychoses, obsessive compulsive and panic disorders (US Patent Application 2003/0032579). Studies in rats (Kostowski et. al “Papaverine drug induced stereotypy and catalepsy and biogenic amines in the brain of the rat” Pharmacol. Biochem. Behav. 1976, 5, 15-17) have showed that papaverine, a selective PDE10 inhibitor, reduces apomorphine induced stereotypes and rat brain dopamine levels and increases haloperidol induced catalepsy. This experiment lends support to the use of a PDE10 inhibitor as an antipsychotic since similar trends are seen with known, marketed antipsychotics.

Antipsychotic medications are the mainstay of current treatment for schizophrenia. Conventional or classic antipsychotics, typified by haloperidol, were introduced in the mid-1950s and have a proven track record over the last half century in the treatment of schizophrenia. While these drugs are effective against the positive, psychotic symptoms of schizophrenia, they show little benefit in alleviating negative symptoms or the cognitive impairment associated with the disease. In addition, drugs such as haloperidol have extreme side effects such as extrapyramidal symptoms (EPS) due to their specific dopamine D2 receptor interaction. An even more severe condition characterized by significant, prolonged, abnormal motor movements known as tardive dyskinesia also may emerge with prolonged classic antipsychotic treatment.

The 1990s saw the development of several new drugs for schizophrenia, referred to as atypical antipsychotics, typified by risperidone and olanzapine and most effectively, clozapine. These atypical antipsychotics are generally characterized by effectiveness against both the positive and negative symptoms associated with schizophrenia, but have little effectiveness against cognitive deficiencies and persisting cognitive impairment remain a serious public health concern (Davis, J. M et al. “Dose response and dose equivalence of antipsychotics.” Journal of Clinical Psychopharmacology, 2004, 24 (2), 192-208; Friedman, J. H. et al “Treatment of psychosis in Parkinson's disease: Safety considerations.” Drug Safety, 2003, 26 (9), 643-659). In addition, the atypical antipsychotic agents, while effective in treating the positive and, to some degree, negative symptoms of schizophrenia, have significant side effects. For example, clozapine which is one of the most clinically effective antipsychotic drugs shows agranulocytosis in approximately 1.5% of patients with fatalities due to this side effect being observed. Other atypical antipsychotic drugs have significant side effects including metabolic side effects (type 2 diabetes, significant weight gain, and dyslipidemia), sexual dysfunction, sedation, and potential cardiovascular side effects that compromise their clinically effectiveness. In the large, recently published NIH sponsored CATIE study, (Lieberman et al “The Clinical Antipsychotic Trials Of Intervention Effectiveness (CATIE) Schizophrenia Trial: clinical comparison of subgroups with and without the metabolic syndrome.” Schizophrenia Research, 2005, 80 (1), 9-43) 74% of patients discontinued use of their antipsychotic medication within 18 months due to a number of factors including poor tolerability or incomplete efficacy. Therefore, a substantial clinical need still exists for more effective and better tolerated antipsychotic mediations possibly through the use of PDE10 inhibitors.

BRIEF SUMMARY

The disclosure relates compounds which are inhibitors of phosphodiesterase 10. The disclosure further relates to processes, pharmaceutical compositions, pharmaceutical preparations and pharmaceutical use of the compounds in the treatment of mammals, including human(s) for central nervous system (CNS) disorders and other disorders which may affect CNS function. The disclosure also relates to methods for treating neurological, neurodegenerative and psychiatric disorders including but not limited to those comprising cognitive deficits or schizophrenic symptoms.

Described herein are compounds of Formula (I) that are inhibitors of at least one phosphodiesterase 10:

Wherein:

HET is a heterocyclic ring selected from Formulas A29, A31 and A39 below

and the left most radical is connected to the X group; X is selected from optionally substituted aryl and optionally substituted heteroaryl; Z is optionally substituted heteroaryl; Each R₂ is independently selected from C₁-C₄ alkyl, or two R₂ groups taken together with the carbon to which they are attached form a 3 membered cycloalkyl ring;

In one embodiment, alkyl groups are fully saturated whether present on their own or as part of another group (e.g. alkylamino or alkoxy).

In certain embodiments, substituent groups are not further substituted.

In various embodiments, any group that is defined as being optionally substituted can be singly or independently multiply optionally substituted.

In one embodiment, HET is selected from Formulas A29 and A31.

In another embodiment, HET is Formula A29.

In another embodiment, HET is Formula A31.

In one embodiment, X is selected from a monocyclic heteroaryl having 5 ring atoms selected from C, O, S and N provided the total number of ring heteroatoms is less than or equal to four and where no more than one of the total number of heteroatoms is oxygen or sulfur, and a monocyclic aromatic ring having 6 atoms selected from C and N provided that not more than 3 ring atoms are N, and where said ring may be optionally and independently substituted with up to two groups selected from C₁-C₄ alkyl, cycloalkyl, cycloalkyloxy, C₁-C₄ alkoxy, CF₃, carboxy, alkoxyalkyl, C₁-C₄ cycloalkylalkoxy, amino, alkylamino, dialkylamino, amido, alkylamido, dialkylamido, thioalkyl, halogen, cyano, alkylsulfonyl and nitro. Examples include but are not limited to 1H-pyrrolyl, furanyl, thiophenyl, imidazolyl, pyrazolyl, isothiazolyl, isoxazolyl, oxazolyl, thiazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, tetrazolyl, 1,2,3,4-oxatriazolyl, 1,2,3,5-oxatriazolyl, 1,2,3,4-thiatriazolyl, 1,2,3,5-thiatriazolyl, 1,2,3-triazinyl, 1,2,4-triazinyl, 1,3,5-triazinyl, pyridinyl, pyrazinyl, pyridazinyl and pyrimidinyl.

In a further embodiment, X is a monocyclic heteroaryl having 6 ring atoms selected from C and N provided that not more than 3 ring atoms are N, and where said ring may be optionally and independently substituted with up to two groups selected from C₁-C₄ alkyl, cycloalkyl, cycloalkyloxy, C₁-C₄ alkoxy, CF₃, carboxy, alkoxyalkyl, C₁-C₄ cycloalkylalkoxy, amino, alkylamino, dialkylamino, amido, alkylamido, dialkylamido, thioalkyl, halogen, cyano, alkylsulfonyl and nitro. Examples include but are not limited to 1,2,3-triazinyl, 1,2,4-triazinyl, 1,3,5-triazinyl, pyridinyl, pyrazinyl, pyridazinyl and pyrimidinyl.

In a further embodiment, X is a monocyclic heteroaryl having 5 ring atoms selected from C, O, S, and N, provided the total number of ring heteroatoms is less than or equal to four and where no more than one of the total number of heteroatoms is oxygen or sulfur and where said ring may be optionally and independently substituted with up to two groups selected from C₁-C₄ alkyl, cycloalkyl, cycloalkyloxy, C₁-C₄ alkoxy, CF₃, carboxy, alkoxyalkyl, C₁-C₄ cycloalkylalkoxy, amino, alkylamino, dialkylamino, amido, alkylamido, dialkylamido, thioalkyl, halogen, cyano, alkylsulfonyl and nitro. Examples include but are not limited to 1H-pyrrolyl, furanyl, thiophenyl, imidazolyl, pyrazolyl, isothiazolyl, isoxazolyl, oxazolyl, thiazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, tetrazolyl, 1,2,3,4-oxatriazolyl, 1,2,3,5-oxatriazolyl, 1,2,3,4-thiatriazolyl, 1,2,3,5-thiatriazolyl.

In a further embodiment, X is 4-pyridinyl optionally substituted with one group selected from C₁-C₄ alkyl, cyclopropyl, cyclopropyloxy, cyclopropylmethyl, C₁-C₄ alkoxy, CF₃, amino, alkylamino, dialkylamino, thioalkyl, halogen, alkylsulfonyl and cyano.

In a further embodiment, X is 4-pyridinyl.

In another embodiment X is selected from restricted phenyl.

In a further embodiment, X is selected from a 3,4-disubstituted phenyl, 4-substituted phenyl. and 4-pyridinyl.

In a further embodiment, X is selected from a 3,4-disubstituted phenyl and 4-substituted phenyl.

In another embodiment, X is selected from 4-pyridinyl and 4-substituted phenyl.

In an additional embodiment, X is 4-substituted phenyl.

In a further embodiment, X is 4-methoxyphenyl.

In another embodiment, X is 4-chlorophenyl.

In another embodiment, X is 4-cyanophenyl.

In one embodiment, Z is heteroaryl but is not quinolinyl or pyridyl.

In one embodiment, Z is heteroaryl but is not quinolinyl.

In one embodiment, Z is heteroaryl but is not pyridyl.

In one embodiment, Z is not pyridin-2-yl.

In one embodiment, Z is not pyridinyl.

In another embodiment, Z is selected from pyridin-2-yl, imidazo[1,2-a]pyridin-2-yl, imidazo[1,2-b]pyridazin-2-yl, and imidazo[1,2-b]pyridazin-6-yl all of which may be optionally substituted with up to 2 substituents independently selected from C₁-C₄ alkyl, cycloalkyl, cycloalkyloxy, C₁-C₄ alkoxy, CF₃, carboxy, alkoxyalkyl, C₁-C₄ cycloalkylalkoxy, amino, alkylamino, dialkylamino, amido, alkylamido, dialkylamido, thioalkyl, halogen, cyano, alkylsulfonyl and nitro.

In a further embodiment, Z is selected from imidazo[1,2-a]pyridin-2-yl, imidazo[1,2-b]pyridazin-2-yl, and imidazo[1,2-b]pyridazin-6-yl all of which may be optionally substituted with up to 2 substituents independently selected from C₁-C₄ alkyl, C₁-C₄ alkoxy, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkyloxy, cycloalkylalkyl, cycloalkylalkoxy, halogen, alkylsulfonyl and cyano.

In a further embodiment, Z is a 3,5-disubstituted-pyridin-2-yl with each substituent being independently selected from C₁-C₄ alkyl, C₁-C₄ alkoxy, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkyloxy, cycloalkylalkyl, cycloalkylalkoxy, halogen, alkylsulfonyl and cyano.

In a further embodiment, Z is 5-substituted-pyridin-2-yl with the substituent being independently selected from C₁-C₄ alkyl, C₁-C₄ alkoxy, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkyloxy, cycloalkylalkyl, cycloalkylalkoxy, halogen, alkylsulfonyl and cyano.

In an additional embodiment, Z is imidazo[1,2-a]pyridin-2-yl substituted with up to 2 substituents independently selected from C₁-C₄ alkyl, C₁-C₄ alkoxy, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkyloxy, cycloalkylalkyl, cycloalkylalkoxy, halogen, alkylsulfonyl and cyano.

In an additional embodiment, Z is imidazo[1,2-b]pyridazin-2-yl substituted with up to 2 substituents independently selected from C₁-C₄ alkyl, C₁-C₄ alkoxy, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkyloxy, cycloalkylalkyl, cycloalkylalkoxy, halogen, alkylsulfonyl and cyano.

In an additional embodiment, Z is imidazo[1,2-b]pyridazin-6-yl substituted with up to 2 substituents independently selected from C₁-C₄ alkyl, C₁-C₄ alkoxy, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkyloxy, cycloalkylalkyl, cycloalkylalkoxy, halogen, alkylsulfonyl and cyano.

In a further embodiment, any Z substituent may be unsubstituted.

In one embodiment, R₂ is C₁-C₄ alkyl.

In another embodiment, R₂ is methyl.

In another embodiment, two R₂ groups taken together form a 3 membered cycloalkyl ring.

Compounds of the disclosure may contain asymmetric centers and exist as different enantiomers or diastereomers or a combination of these therein. All enantiomeric, diastereomeric forms of Formula (I) are embodied herein.

Compounds in the disclosure may be in the form of pharmaceutically acceptable salts. The phrase “pharmaceutically acceptable” refers to salts prepared from pharmaceutically acceptable non-toxic bases and acids, including inorganic and organic bases and inorganic and organic acids. Salts derived from inorganic bases include lithium, sodium, potassium, magnesium, calcium and zinc. Salts derived from organic bases include ammonia, primary, secondary and tertiary amines, and amino acids. Salts derived from inorganic acids include sulfuric, hydrochloric, phosphoric, hydrobromic. Salts derived from organic acids include C₁₋₆ alkyl carboxylic acids, di-carboxylic acids and tricarboxylic acids such as acetic acid, proprionic acid, fumaric acid, maleic acid, succinic acid, tartaric acid, adipic acid and citric acid, and alkylsulfonic acids such as methanesulphonic, and aryl sulfonic acids such as para-tolouene sulfonic acid and benzene sulfonic acid.

Compounds in the disclosure may be in the form of a solvate. This occurs when a compound of Formula (I) has an energetically favorable interaction with a solvent, crystallizes in a manner that it incorporates solvent molecules into the crystal lattice or a complex is formed with solvent molecules in the solid or liquid state. Examples of solvents forming solvates are water (hydrates), MeOH, EtOH, iPrOH, and acetone.

Compounds in the disclosure may exist in different crystal forms known as polymorphs. Polymorphism is the ability of a substance to exist in two or more crystalline phases that have different arrangements and/or conformations of the molecule in the crystal lattice.

Compounds in the disclosure may exist as isotopically labeled compounds of Formula (I) where one or more atoms are replaced by atoms having the same atomic number but a different atomic mass from the atomic mass which is predominantly seen in nature. Examples of isotopes include, but are not limited to hydrogen isotopes (deuterium, tritium), carbon isotopes (¹¹C, ¹³C, ¹⁴C) and nitrogen isotopes (¹³N, ¹⁵N). For example, substitution with heavier isotopes such as deuterium (²H) may offer certain therapeutic advantages resulting from greater metabolic stability which could be preferable and lead to longer in vivo half-life or dose reduction in a mammal or human.

Prodrugs of compounds embodied by Formula (I) are also within the scope of this disclosure. Particular derivatives of compounds of Formula (I) which may have little to negligible pharmacological activity themselves, can, when administered to a mammal or human, be converted into compounds of Formula (I) having the desired biological activity.

Compounds in the disclosure and their pharmaceutically acceptable salts, prodrugs, as well as metabolites of the compounds, may also be used to treat certain eating disorders, obesity, compulsive gambling, sexual disorders, narcolepsy, sleep disorders, diabetes, metabolic syndrome, neurodegenerative disorders and CNS disorders/conditions as well as in smoking cessation treatment.

In one embodiment the treatment of CNS disorders and conditions by the compounds of the disclosure can include Huntington's disease, schizophrenia and schizo-affective conditions, delusional disorders, drug-induced psychoses, panic and obsessive compulsive disorders, post-traumatic stress disorders, age-related cognitive decline, attention deficit/hyperactivity disorder, bipolar disorders, personality disorders of the paranoid type, personality disorders of the schizoid type, psychosis induced by alcohol, amphetamines, phencyclidine, opioids hallucinogens or other drug-induced psychosis, dyskinesia or choreiform conditions including dyskinesia induced by dopamine agonists, dopaminergic therapies, psychosis associated with Parkinson's disease, psychotic symptoms associated with other neurodegenerative disorders including Alzheimer's disease, dystonic conditions such as idiopathic dystonia, drug-induced dystonia, torsion dystonia, and tardive dyskinesia, mood disorders including major depressive episodes, post-stroke depression, minor depressive disorder, premenstrual dysphoric disorder, dementia including but not limited to multi-infarct dementia, AIDS-related dementia, and neurodegenerative dementia.

In another embodiment, compounds of the disclosure may be used for the treatment of eating disorders, obesity, compulsive gambling, sexual disorders, narcolepsy, sleep disorders as well as in smoking cessation treatment.

In a further embodiment, compounds of the disclosure may be used for the treatment of obesity, schizophrenia, schizo-affective conditions, Huntington's disease, dystonic conditions and tardive dyskinesia.

In another embodiment, compounds of the disclosure may be used for the treatment of schizophrenia, schizo-affective conditions, Huntington's disease and obesity.

In a further embodiment, compounds of the disclosure may be used for the treatment of schizophrenia and schizo-affective conditions.

In an additional embodiment, compounds of the disclosure may be used for the treatment of Huntington's disease.

In another embodiment, compounds of the disclosure may be used for the treatment of obesity and metabolic syndrome.

Compounds of the disclosure may also be used in mammals and humans in conjunction with conventional antipsychotic medications including but not limited to Clozapine, Olanzapine, Risperidone, Ziprasidone, Haloperidol, Aripiprazole, Sertindole and Quetiapine. The combination of a compound of Formula (I) with a subtherapeutic dose of an aforementioned conventional antipsychotic medication may afford certain treatment advantages including improved side effect profiles and lower dosing requirements.

DEFINITIONS

Alkyl is meant to denote a linear or branched saturated or unsaturated aliphatic C₁-C₈ hydrocarbon which can be optionally substituted with up to 3 fluorine atoms and, if specified, substituted with other groups. Unsaturation in the form of a double or triple carbon-carbon bond may be internal or terminally located and in the case of a double bond both cis and trans isomers are included. Examples of alkyl groups include but are not limited to methyl, trifluoromethyl, ethyl, trifluoroethyl, isobutyl, neopentyl, cis- and trans-2-butenyl, isobutenyl, propargyl. C₁-C₄ alkyl is the subset of alkyl limited to a total of up to 4 carbon atoms.

In each case in which a size range for the number of atoms in a ring or chain is disclosed, all subsets are disclosed. Thus, C_(x)-C_(y) includes all subsets, e.g., C₁-C₄ includes C₁-C₂, C₂-C₄, C₁-C₃ etc.

Acyl is an alkyl-C(O)— group wherein alkyl is as defined above. Examples of acyl groups include acetyl and proprionyl.

Alkoxy is an alkyl-O— group wherein alkyl is as defined above. C₁-C₄ alkoxy is the subset of alkyl-O— where the subset of alkyl is limited to a total of up to 4 carbon atoms. Examples of alkoxy groups include methoxy, trifluoromethoxy, ethoxy, trifluoroethoxy, and propoxy.

Alkoxyalkyl is an alkyl-O—(C₁-C₄ alkyl)- group wherein alkyl is as defined above. Examples of alkoxyalkyl groups include methoxymethyl and ethoxymethyl.

Alkoxyalkyloxy is an alkoxy-alkyl-O— group wherein alkoxy and alkyl are as defined above. Examples of alkoxyalkyloxy groups include methoxymethyloxy (CH₃OCH₂O—) and methoxyethyloxy (CH₃OCH₂CH₂O—) groups.

Alkylthio is alkyl-S— group wherein alkyl is as defined above. Alkylthio includes C₁-C₄ alkylathio.

Alkylsulfonyl is alkyl-SO₂— wherein alkyl is as defined above. Alkylsulfonyl includes C₁-C₄ alkylsulfonyl.

Alkylamino is alkyl-NH— wherein alkyl is as defined above. Alkylamino includes C₁-C₄ alkylamino.

Dialkylamino is (alkyl)₂-N— wherein alkyl is as defined above.

Amido is H₂NC(O)—

Alkylamido is alkyl-NHC(O)— wherein alkyl is as defined above.

Dialkylamido is (alkyl)₂-NC(O)— wherein alkyl is as defined above.

Aromatic is heteroaryl or aryl wherein heteroaryl and aryl are as defined below.

Aryl is a phenyl or napthyl group. Aryl groups may be optionally and independently substituted with up to three groups selected from halogen, CF₃, CN, NO₂, OH, alkyl, cycloalkyl, cycloalkylalkyl, alkoxy, alkoxyalkyl, aryloxy, alkoxyalkyloxy, heterocycloalkyl, heterocycloalkylalkyl, heterocycloalkyloxy, heteroaryl, heteroaryloxy, —OCH₂CH₂OCH₃, —OC(O)R_(a), —OC(O)OR_(a), —OC(O)NHR_(a), —OC(O)N(R_(a)), —SR_(a), —S(O)R_(a), —NH₂, —NHR_(a), —N(R_(a))(R_(b)), —NHC(O)R_(a), —N(R_(a))C(O)R_(b), —NHC(O)OR_(a), —N(ROC(O)OR_(b), —N(R_(a))C(O)NH(R_(b)), —N(ROC(O)NH(R_(b))₂, —C(O)NH₂, —C(O)NHR_(a), —C(O)N(R_(a))(R_(b)), —CO₂H, —CO₂R_(a), —COR_(a) wherein R_(a) and R_(b) are independently chosen from alkyl, alkoxyalkyl, —CH₂CH₂OH, —CH₂CH₂OMe, cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, heterocycloalkyl, and heterocycloalkylalkyl, each of which is optionally and independently substituted with up to three groups selected from only halogen, Me, Et, ^(i)Pr, ^(t)Bu, unsubstituted cyclopropyl, unsubstituted cyclobutyl, CN, NO₂, NH₂, CF₃, NHMe, NMe₂, OMe, OCF₃, each of which are attached via carbon-carbon or carbon-nitrogen or carbon-oxygen single bonds; or R_(a) and R_(b) taken together with the atom(s) to which they are attached form a 5-6 membered ring.

Arylalkyl is an aryl-alkyl- group wherein aryl and alkyl are as defined above.

Aryloxy is an aryl-O— group wherein aryl is as defined above.

Arylalkoxy is an aryl-(C₁-C₄ alkyl)-O— group wherein aryl is as defined above.

Carboxy is a CO₂H or CO₂R_(c) group wherein R_(c) is independently chosen from, alkyl, C₁-C₄ alkyl, cycloalkyl, arylalkyl, cycloalkylalkyl, CF₃, and alkoxyalkyl, wherein alkyl is as defined above.

Cycloalkyl is a C₃-C₇ cyclic non-aromatic hydrocarbon which may contain a single double bond and is optionally and independently substituted with up to three groups selected from alkyl, alkoxy, hydroxyl and oxo. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclopentenyl and cyclohexanonyl.

Cycloalkyloxy is a cycloalkyl-O— group wherein cycloalkyl is as defined above. Examples include cyclopropyloxy, cyclobutyloxy and cyclopentyloxy. C₃-C₆ cycloalkyloxy is the subset of cycloalkyl-O— where cycloalkyl contains 3-6 carbon atoms.

Cycloalkylalkyl is a cycloalkyl-(C₁-C₄ alkyl)- group. Examples include cyclopropylmethyl, cyclopropylethyl, cyclohexylmethyl and cyclohexylethyl.

Cycloalkylalkoxy is a cycloalkyl-(C₁-C₄ alkyl)-O— group wherein cycloalkyl and alkyl are as defined above. Examples of cycloalkylalkoxy groups include cyclopropylmethoxy, cyclopentylmethoxy and cyclohexylmethoxy.

Halogen is F, Cl, Br or I.

Heteroaryl is a tetrazole, 1,2,3,4-oxatriazole, 1,2,3,5-oxatriazole, a mono or bicyclic aromatic ring system, or a heterobicyclic ring system with one aromatic ring having 5 to 10 ring atoms independently selected from C, N, O and S, provided that not more than 3 ring atoms in any single ring are other than C. Examples of heteroaryl groups include but are not limited to thiophenyl, furanyl, thiazolyl, isothiazolyl, oxazolyl, isoxazolyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, pyrrazolyl, imidazolyl, 1,2,3-triazolyl, 1,3,4-triazolyl, pyrimidinyl, pyrazinyl, indolyl, quinolyl, tetrahydroquinolyl, isoquinolyl, tetrahydroisoquinolyl, indazolyl, benzthiadiazololyl, benzoxadiazolyl and benzimidazolyl. Heteroaryl groups may be optionally and independently substituted with up to 3 substituents independently selected from halogen, CF₃, CN, NO₂, OH, alkyl, cycloalkyl, cycloalkylalkyl, alkoxy, alkoxyalkyl, aryloxy, alkoxyalkyloxy, heterocycloalkyl, heterocycloalkylalkyl, heterocycloalkyloxy, heteroaryl, heteroaryloxy, —OCH₂CH₂OCH₃, —OC(O)R_(a), —OC(O)O R_(a), —OC(O)NHR_(a), —OC(O)N(R_(a)), —SR_(a), —S(O)R_(a), —NH₂, —NHR_(a), —N(R_(a))(R_(b)), —NHC(O)R_(a), —N(R_(a)) C(O)R_(b), —NHC(O)OR_(a), —N(R_(a))C(O)OR_(b), —N(R_(a))C(O)NH(R_(b)), —N(R_(a))C(O)NH(R_(b))₂, —C(O)NH₂, —C(O)NHR_(a), —C(O)N(R_(a))(R_(b)), —CO₂H, —CO₂R_(a), —COR_(a) wherein R_(a) and R_(b) are independently chosen from alkyl, alkoxyalkyl, —CH₂CH₂OH, —CH₂CH₂OMe, cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, heterocycloalkyl, and heterocycloalkylalkyl, each of which is optionally and independently substituted with up to three groups selected from only halogen, Me, Et, ^(i)Pr, ^(t)Bu, unsubstituted cyclopropyl, unsubstituted cyclobutyl, CN, NO₂, NH₂, CF₃, NHMe, NMe₂, OMe, OCF₃, each of which are attached via carbon-carbon or carbon-nitrogen or carbon-oxygen single bonds; or R_(a) and R_(b) taken together with the atom(s) to which they are attached form a 5-6 membered ring.

Heteroarylalkyl is a heteroaryl-(C₁-C₄ alkyl)- group wherein heteroaryl and alkyl are as defined above. Examples of heteroarylalkyl groups include 4-pyridinylmethyl and 4-pyridinylethyl.

Heteroaryloxy is a heteroaryl-O group wherein heteroaryl is as defined above.

Heteroarylalkoxy is a heteroaryl-(C₁-C₄ alkyl)-O— group wherein heteroaryl and alkoxy are as defined above. Examples of heteroarylalkyl groups include 4-pyridinylmethoxy and 4-pyridinylethoxy.

Heterobicyclic ring system is a ring system having 8-10 atoms independently selected from C, N, O and S, provided that not more than 3 ring atoms in any single ring are other than carbon and provided that at least one of the rings is aromatic; said bicyclic ring may be optionally and independently substituted with up to 3 substituents independently selected from alkyl, alkoxy, cycloalkyl, C₃-C₆ cycloalkyloxy, cycloalkylalkyl, halogen, nitro, alkylsulfonyl and cyano. Examples of 8-10 membered heterobicyclic ring systems include but are not limited to 1,5-naphthyridyl, 1,2,3,4-tetrahydro-1,5-naphthyridyl 1,6-naphthyridyl, 1,2,3,4-tetrahydro-1,6-naphthyridyl 1,7-naphthyridyl, 1,2,3,4-tetrahydro-1,7-naphthyridinyl 1,8-naphthyridyl, 1,2,3,4-tetrahydro-1,8-naphthyridyl, 2,6-naphthyridyl, 2,7-naphthyridyl, cinnolyl, isoquinolyl, tetrahydroisoquinolinyl, phthalazyl, quinazolyl, 1,2,3,4-tetrahydroquinazolinyl, quinolyl, tetrahydroquinolinyl, quinoxalyl, tetrahydroquinoxalinyl, benzo[d][1,2,3]triazyl, benzo[e][1,2,4]triazyl, pyrido[2,3-b]pyrazyl, pyrido[2,3-c]pyridazyl, pyrido[2,3-d]pyrimidyl, pyrido[3,2-b]pyrazyl, pyrido[3,2-c]pyridazyl, pyrido[3,2-d]pyrimidyl, pyrido[3,4-b]pyrazyl, pyrido[3,4-c]pyridazyl, pyrido[3,4-d]pyrimidyl, pyrido[4,3-b]pyrazyl, pyrido[4,3-c]pyridazyl, pyrido[4,3-d]pyrimidyl, quinazolyl, 1H-benzo[d][1,2,3]triazoyl, 1H-benzo[d]imidazoyl, 1H-indazoyl, 1H-indoyl, 2H-benzo[d][1,2,3]triazoyl, 2H-pyrazolo[3,4-b]pyridinyl, 2H-pyrazolo[4,3-b]pyridinyl, [1,2,3]triazolo[1,5-a]pyridinyl, [1,2,4]triazolo[1,5-a]pyridinyl, [1,2,4]triazolo[4,3-a]pyridinyl, benzo[b]thienyl, benzo[c][1,2,5]oxadiazyl, benzo[c][1,2,5]thiadiazolyl, benzo[d]isothiazoyl, benzo[d]isoxazoyl, benzo[d]oxazoyl, benzo[d]thiazoyl, benzofuryl, imidazo[1,2-a]pyrazyl, imidazo[1,2-a]pyridinyl, imidazo[1,2-a]pyrimidyl, imidazo[1,2-b]pyridazyl, imidazo[1,2-c]pyrimidyl, imidazo[1,5-a]pyrazyl, imidazo[1,5-a]pyridinyl, imidazo[1,5-a]pyrimidyl, imidazo[1,5-b]pyridazyl, imidazo[1,5-c]pyrimidyl, indolizyl, pyrazolo[1,5-a]pyrazyl, pyrazolo[1,5-a]pyridinyl, pyrazolo[1,5-a]pyrimidyl, pyrazolo[1,5-b]pyridazine, pyrazolo[1,5-c]pyrimidine, pyrrolo[1,2-a]pyrazine, pyrrolo[1,2-a]pyrimidyl, pyrrolo[1,2-b]pyridazyl, pyrrolo[1,2-c]pyrimidyl, 1H-imidazo[4,5-b]pyridinyl, 1H-imidazo[4,5-c]pyridinyl, 1H-pyrazolo[3,4-b]pyridinyl, 1H-pyrazolo[3,4-c]pyridinyl, 1H-pyrazolo[4,3-b]pyridinyl, 1H-pyrazolo[4,3-c]pyridinyl, 1H-pyrrolo[2,3-b]pyridinyl, 1H-pyrrolo[2,3-c]pyridinyl, 1H-pyrrolo[3,2-b]pyridinyl, 1H-pyrrolo[3,2-c]pyridinyl, 2H-indazoyl, 3H-imidazo[4,5-b]pyridinyl, 3H-imidazo[4,5-c]pyridinyl, benzo[c]isothiazyl, benzo[c]isoxazyl, furo[2,3-b]pyridinyl, furo[2,3-c]pyridinyl, furo[3,2-b]pyridinyl, furo[3,2-c]pyridinyl, isothiazolo[4,5-b]pyridinyl, isothiazolo[4,5-c]pyridinyl, isothiazolo[5,4-b]pyridinyl, isothiazolo[5,4-c]pyridinyl, isoxazolo[4,5-b]pyridinyl, isoxazolo[4,5-c]pyridinyl, isoxazolo[5,4-b]pyridinyl, isoxazolo[5,4-c]pyridinyl, oxazolo[4,5-b]pyridinyl, oxazolo[4,5-c]pyridinyl, oxazolo[5,4-b]pyridinyl, oxazolo[5,4-c]pyridinyl, thiazolo[4,5-b]pyridiyl, thiazolo[4,5-c]pyridinyl, thiazolo[5,4-b]pyridinyl, thiazolo[5,4-c]pyridinyl, thieno[2,3-b]pyridinyl, thieno[2,3-c]pyridinyl, thieno[3,2-b]pyridinyl and thieno[3,2-c]pyridinyl.

Heterocycloalkyl is a non-aromatic, monocyclic or bicyclic saturated or partially unsaturated ring system comprising 5-10 ring atoms selected from C, N, O and S, provided that not more than 2 ring atoms in any single ring are other than C. In the case where the heterocycloalkyl group contains a nitrogen atom the nitrogen may be substituted with an alkyl, acyl, —C(O)O-alkyl, —C(O)NH(alkyl) or a —C(O)N(alkyl)₂ group. Heterocycloalkyl groups may be optionally and independently substituted with hydroxy, alkyl and alkoxy groups and may contain up to two oxo groups. Heterocycloalkyl groups may be linked to the rest of the molecule via either carbon or nitrogen ring atoms. Examples of heterocycloalkyl groups include tetrahydrofuranyl, tetrahydrothienyl, tetrahydro-2H-pyran, tetrahydro-2H-thiopyranyl, pyrrolidinyl, pyrrolidonyl, succinimidyl, piperidinyl, piperazinyl, N-methylpiperazinyl, morpholinyl, morpholin-3-one, thiomorpholinyl, thiomorpholin-3-one, 2,5-diazabicyclo[2.2.2]octanyl, 2,5-diazabicyclo[2.2.1]heptanyl, octahydro-1H-pyrido[1,2-a]pyrazine, 3-thia-6-azabicyclo[3.1.1]heptane and 3-oxa-6-azabicyclo[3.1.1]heptanyl.

Heterocycloalkylalkyl is a heterocycloalkyl-(C₁-C₄ alkyl)- group wherein heterocycloalkyl is as defined above.

Heterocycloalkyloxy is a heterocycloalkyl-O— group wherein heterocycloalkyl is as defined above.

Heterocycloalkylalkoxy is a heterocycloalkyl-(C₁-C₄ alkyl)-O— group wherein heterocycloalkyl is as defined above.

Oxo is a —C(O)— group.

Phenyl is a benzene ring which may be optionally and independently substituted with up to three groups selected from halogen, CF₃, CN, NO₂, OH, alkyl, cycloalkyl, cycloalkylalkyl, alkoxy, alkoxyalkyl, aryloxy, alkoxyalkyloxy, heterocycloalkyl, heterocycloalkylalkyl, heterocycloalkyloxy, heteroaryl, heteroaryloxy, —OCH₂CH₂OCH₃, —OC(O)R_(a), —OC(O)OR_(a), —OC(O)NHR_(a), —OC(O)N(R_(a)), —SR_(a), —S(O)R_(a), —NH₂, —NHR_(a), —N(R_(a))(R_(b)), —NHC(O)R_(a), —N(ROC(O)R_(b), —NHC(O)OR_(a), —N(R_(a))C(O)OR_(b), —N(R_(a))C(O)NH(R_(b)), —N(ROC(O)NH(R_(b))₂, —C(O)NH₂, —C(O)NHR_(a), —C(O)N(R_(a))(R_(b)), —CO₂H, —CO₂R_(a), —COR_(a) wherein R_(a) and R_(b) are independently chosen from alkyl, alkoxyalkyl, —CH₂CH₂OH, —CH₂CH₂OMe, cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, heterocycloalkyl, and heterocycloalkylalkyl, each of which is optionally and independently substituted with up to three groups selected from only halogen, Me, Et, ^(i)Pr, ^(t)Bu, unsubstituted cyclopropyl, unsubstituted cyclobutyl, CN, NO₂, NH₂, CF₃, NHMe, NMe₂, OMe, OCF₃, each of which are attached via carbon-carbon or carbon-nitrogen or carbon-oxygen single bonds; or R_(a) and R_(b) taken together with the atom(s) to which they are attached form a 5-6 membered ring.

Restricted phenyl is a benzene ring which may be optionally and independently substituted with up to three groups selected from halogen, CF₃, CN, alkoxy, alkoxyalkyl, aryloxy, alkoxyalkyloxy, heterocycloalkyl, heterocycloalkyloxy, heteroaryl, heteroaryloxy, —OCH₂CH₂OCH₃, —OC(O)R_(a), —OC(O)OR_(a), —OC(O)N(R_(a)), —N(R_(a))(R_(b)), —NHC(O)R_(a), —N(R_(a))C(O)R_(b), —NHC(O)OR_(a), —N(R_(a))C(O)OR_(b), —C(O)N(R_(a))(R_(b)), —COR_(a) wherein R_(a) and R_(b) are independently chosen from alkyl, alkoxyalkyl, —CH₂CH₂OH, —CH₂CH₂OMe, cycloalkyl, cycloalkylalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, heterocycloalkyl, and heterocycloalkylalkyl, each of which is optionally and independently substituted with up to three groups selected from only halogen, Me, Et, ^(i)Pr, ^(t)Bu, unsubstituted cyclopropyl, unsubstituted cyclobutyl, CN, NO₂, NH₂, CF₃, NHMe, NMe₂, OMe, OCF₃, each of which are attached via carbon-carbon or carbon-nitrogen or carbon-oxygen single bonds; or R_(a) and R_(b) taken together with the atom(s) to which they are attached form a 5-6 membered ring.

Abbreviations used in the following examples and preparations include:

-   -   Ac Acyl (Me-C(O)—)     -   AcN Acetonitrile     -   BINAP 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl     -   Bn Benzyl     -   Celite® Diatomaceous earth     -   DBU 1,8-Diazabicyclo[5.4.0]undec-7-ene     -   DCC N.N′, Dicyclohexylcarbodiimide     -   DCM Dichloromethane     -   DIEA Di-isopropylethyl amine     -   DIPEA Di-isopropylethyl amine     -   DMAP 4-Dimethylaminopyridine     -   DMF Dimethylformamide     -   DMP Dess Martin Periodinane     -   DMSO Dimethyl sulfoxide     -   Dppf 1,4-Bis(diphenylphosphino) ferrocene     -   EDC 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide Hydrochloride     -   Et₃N Triethylamine     -   g gram(s)     -   h Hour(s)     -   hr Hour(s)     -   HATU 2-(7-Aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium         hexafluorophosphate     -   HMDS Hexamethyldisilazide     -   HOBt 1-Hydroxybenzotriazole     -   HPLC High Pressure Liquid Chromatography     -   HRMS High resolution mass spectrometry     -   i.v. Intravenous     -   KHMDS Potassium Hexamethydisilazide     -   LDA Lithium Di-isopropylamide     -   m Multiplet     -   m- meta     -   MEM Methoxyethoxymethyl     -   MeOH Methyl Alcohol or Methanol     -   min Minute(s)     -   mmol millimoles     -   mmole millimoles     -   Ms Mesylate     -   MS Mass Spectrometry     -   MW Molecular Weight     -   NBS N-Bromosuccinamide     -   NIS N-Iodosuccinamide     -   NMR Nuclear Magnetic Resonance     -   NMM N-Methyl Morpholine     -   NMP N-Methyl-2-pyrrolidone     -   o ortho     -   o/n overnight     -   P para     -   PCC Pyridinium Chlorochromate     -   PEPPSI         1,3-Bis(2,6-diisopropylphenyl)imidazolidene)(3-chloropyridinyl)         palladium(II) dichloride     -   PhNTf₂         1,1,1-trifluoro-N-phenyl-N-(trifluoromethylsulfonyl)methanesulfonamide     -   POPd Dihydrogen dichlorobis(di-tert-butylphosphinito-kp)         palladate (2-)     -   p.s.i. Pounds per square inch     -   PPA Polyphosphoric acid     -   PPAA 1-Propanephosphonic Acid Cyclic Anhydride     -   PTSA p-Toluenesulfonic acid     -   PyBOP® Benzotriazol-1-yl-oxytripyrrolidinophosphonium         hexafluorophosphate     -   RT (or rt) room temperature (about 20-25° C.)     -   s Singlet     -   sat. Saturated     -   t Triplet     -   TBAF Tetra-butyl ammonium fluoride     -   TEA Triethylamine     -   TFA Trifluoroacetic Acid     -   THF Tetrahydrofuran     -   TLC Thin layer chromatography     -   TMS Trimethylsilyl     -   Tf Triflate     -   Tof-MS Time of Flight Mass Spectrometry     -   Ts Tosylate     -   v/v volume/volume     -   wt/v weight/volume

DETAILED DESCRIPTION

The 1,2 disubstituted heterocyclic compounds of Formula I may be prepared from multi-step organic synthesis routes from commercially available starting materials by one skilled in the art of organic synthesis using established organic synthetic procedures. Non-commercially available phenyl acetic acids can be made from commercially available starting materials via methods known by one skilled in the art of organic synthesis. Such methods include synthesis from the corresponding aryl acids via. the Wolff rearrangement using diazomethane.

Compounds of the disclosure where HET is A29 and A31 may be prepared generally as depicted in Schemes 1-8 below.

Compounds of the disclosure of Formula (I) wherein HET is A29 and X=phenyl or heteroaryl (each respectively optionally substituted) thus having general Formula LIV may be prepared generally as depicted in Scheme 1:

Alternatively, compounds of the disclosure of Formula (I) wherein HET is A29 and X=phenyl or heteroaryl (each respectively optionally substituted) and thus having general Formula LIV may also be prepared generally as depicted in Scheme 2:

Intermediate compounds of Formula LXIII may alternatively be synthesized as depicted in Scheme 3.

Compounds of the disclosure of Formula (I) wherein HET is A31 and X=phenyl or heteroaryl (each optionally substituted) are as described previously and thus having general Formula LXXIV may be prepared generally as depicted in Scheme 4:

The general synthesis of heterocyclic chloride intermediates (Z—CH₂—Cl) where Z corresponds to an imidazo[1,2-a]pyrid-2-yl is depicted in Scheme 5.

The general synthesis of heterocyclic chloride intermediates (Z—CH₂—Cl) where Z corresponds to an imidazo[1,2-b]pyridazin-6-yl is depicted in Scheme 6.

The general synthesis of heterocyclic chloride intermediates (Z—CH₂—Cl) where Z corresponds to an imidazo[1,2-b]pyridazin-2-yl is depicted in Scheme 7.

The general synthesis of heterocyclic chloride intermediates (Z—CH₂—Cl) where Z corresponds to either a 5-substituted-pyridin-2-yl or a 3,5-disubstituted-lpyridin-2-yl is depicted in Scheme 8.

Reactive groups not involved in the above processes can be protected with standard protecting groups during the reactions and removed by standard procedures (T. W. Greene & P. G. M. Wuts, Protecting Groups in Organic Synthesis, Third Edition, Wiley-Interscience) known to those of ordinary skill in the art. Presently preferred protecting groups include methyl, benzyl, MEM, acetate and tetrahydropyranyl for the hydroxyl moiety, and BOC, Cbz, trifluoroacetamide and benzyl for the amino moiety, methyl, ethyl, tert-butyl and benzyl esters for the carboxylic acid moiety. Practitioners in the art will also recognize that the order of certain chemical reactions can be changed. Practitioners of the art will also note that alternative reagents and conditions exist for various chemical steps.

Experimental Procedures

The synthesis of N-methoxy-N-methylcarboxamides from their corresponding carboxylic acids is known by those of ordinary skill in the art. A representative procedure is described below, where is selected from

To a stirred solution of carboxylic acid (1 eq., 3 mmol) in DCM (50 mL) was added HATU (1.5 eq, 4.5 mmol), N-methoxy methylamine (1.5 eq, 4.5 mmol) and TEA (3 eq., 9 mmol) at RT under nitrogen atmosphere. The reaction mixture was then stirred at RT for 3 h. The reaction mixture was diluted with water and the aqueous layer was extracted with DCM (3×50 mL). The combined organic extracts were washed with water (50 mL), brine (20 mL), dried over anhydrous Na₂SO₄, filtered and evaporated under reduced pressure to afford the corresponding N-methoxy-N-methylcarboxamide.

HPLC Conditions Condition-A: Column: Acquity BEH C-18 (50×2.1 mm, 1.7μ,)

-   -   Column Temp: 25° C.     -   Mobile Phase A/B: Acetonitrile (0.025% TFA) and water     -   Flow Rate: 0.50 mL/Min

4-(5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile

To a suspension of NaH (0.9 g) in THF at RT was added 3-hydroxy-3-methyl-2-butanone (1 g) and ethyl methyl 4-cyanobenzoate (1.58 g). The resultant mixture was refluxed overnight, upon which the reaction was quenched with 12N HCl (6 mL). MgSO4 (excess) was added until the organic phase became clear. The solids were removed by filtration and the filtrate was concentrated under reduced pressure. The residue was purified by column chromatography to give 4-(5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (0.63 g).

Synthesis of 4-(4-Hydroxyphenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one 4-Methoxy-N-methoxy-N-methylbenzamide

To a stirred solution of 4-methoxybenzoic acid (10.0 g, 65.70 mmol) in DCM (50 mL) were added EDCI (18.90 g, 98.60 mmol), HOBT (10.0 g, 65.70 mmol), N-methoxy methylamine (13.0 g, 131.40 mmol) and DIPEA (34.3 mL, 197.20 mmol) at RT under a nitrogen atmosphere. The reaction mixture was stirred at RT for 12 h. The reaction mixture was diluted with water and the aqueous layer was extracted with DCM (3×100 mL). The combined organic extracts were washed with water (2×100 mL), brine (2×50 mL), dried over anhydrous Na₂SO₄, filtered and evaporated under reduced pressure to afford crude product. The crude material was purified by flash column chromatography using 20% ethyl acetate in hexane and silica gel (230-400 Mesh) to afford N,4-dimethoxy-N-methylbenzamide (11.0 g, 86%) as a colorless liquid.

4-Hydroxy-1-(4-methoxyphenyl)-4-methylpent-2-yn-1-one

To a stirred solution of 2-methylbut-3-yn-2-ol (2.15 g, 25.6 mmol) in dry THF (80 mL) was added n-BuLi (24.0 mL, 38.7 mmol, 1.6 M in hexane) drop wise at −20° C. under an inert atmosphere for a period of 10 min. After being stirred for 30 min at −20° C., a solution of N,4-dimethoxy-N-methylbenzamide (2.5 g, 12.8 mmol) in dry THF (10 mL) was added to reaction mixture and stirring was continued for an additional 3 h at −20° C. The reaction mixture was quenched with a saturated NH₄Cl solution and extracted with EtOAc (2×100 mL). The combined organic layer was washed with water (100 mL), brine (40 mL), dried over Na₂SO₄, filtered and concentrated in vacuo to afford 4-hydroxy-1-(4-methoxyphenyl)-4-methylpent-2-yn-1-one (2.25 g, 81%) as a colorless liquid.

5-(4-Methoxyphenyl)-2,2-dimethylfuran-3(2H)-one

To 4-hydroxy-1-(4-methoxyphenyl)-4-methylpent-2-yn-1-one (10 g, 45.8 mmol) was added methanolic ammonia (50 mL) at room temperature and the reaction mixture was stirred overnight. The mixture was concentrated under reduced pressure and 50% aqueous acetic acid was added. The resultant mixture was heated at reflux for 4 hours. The pH was adjusted to 8 with saturated ammonium chloride solution and extracted with DCM. The combined organics were washed with water and brine solution, dried over sodium sulphate, filtered, concentrated under reduced pressure and washed with heptane to afford 5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (8.6 g, 86%) as white solid. ¹H NMR (500 MHz, d₆-DMSO): δ 7.99 (d, 2H), 7.15 (d, 2H), 6.20 (s, 1H), 3.89 (s, 3H). 1.42 (s, 6H). MS: [M+H]+: m/z=218.1.

4-Bromo-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one

To a stirred solution of 5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (5.5 g, 0.025 mol) in CHCl₃ (100 mL) was added NBS (6.733 g, 0.038 mol) portion wise at RT. The reaction mixture was stirred for 2 h at RT. The reaction mixture was diluted with DCM (100 mL), washed with water (50 mL), brine (50 mL), dried over Na₂SO₄, filtered and then concentrated in vacuo to obtain the crude product. The crude material was purified via by flash column chromatography using 25% ethyl acetate in hexane and silica gel (230-400 Mesh) to afford 4-bromo-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (4.6 g, 65%) as a solid.

4-(4-(Benzyloxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one

4-Bromo-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (2 g, 6.7 mol), 2-(4-(benzyloxy)phenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.43 g, 0.0067 mol), and Cs₂CO₃ (11 g, 0.034 mol) in toluene (25 mL) and water (8 mL) was degassed, Pd (dppf) Cl₂ (1.1 g, 0.0013 mol) was added under an inert atmosphere and the mixture degassed once again. The reaction was heated at reflux for 3 h, upon which the reaction mixture was filtered through a pad of Celite® and the filtrate was diluted with EtOAc (100 mL), washed with water (50 mL), brine (50 mL), dried over Na₂SO₄, filtered and concentrated in vacuo to obtain the crude product. The crude material was purified by flash column chromatography using 30% ethyl acetate in hexane and silica gel (230-400 Mesh), Rf=0.30 to afford 4-(4-(benzyloxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (2.3 g, 73%) as solid. ¹H NMR (500 MHz, d₆-DMSO): δ 8.42 (d, J=7.6 Hz, 1H), 8.06-7.99 (m, 2H), 7.95 (t, J=7.2 Hz, 1H), 7.72 (t, J=7.2 Hz, 1H), 7.63 (t, J=7.8 Hz, 1H), 7.56 (d, J=7.2 Hz, 2H); 7.18 (d, J=7.4 Hz, 2H), 7.12 (d, J=7.2 Hz, 2H), 6.89 (d, J=7.2 Hz, 2H), 5.38 (s, 2H), 3.79 (s, 3H). 1.42 (s, 6H). MS: [M+H]+: m/z=452.1; [M+Na]+: m/z=474.2.

4-(4-Hydroxyphenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one

5% Palladium on carbon (7.0 g) was added to a solution 4-(4-(benzyloxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (19 g, 42.1 mmol) in methanol (25 ml) at RT under an atmosphere of nitrogen. The nitrogen atmosphere was changed to an atmosphere of hydrogen. The reaction mixture was stirred under an atmosphere of hydrogen at RT for 4 h (the reaction was monitored by TLC). The reaction mixtures was filtered over through a pad of Celite®, washed with methanol, concentrated in vacuo and the resultant residue was slurried with heptane. The solid was filtered & dried under vacuum to afford 4-(4-hydroxyphenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (14.0 g, 95%,) as light yellow solid. ¹H NMR, 500 MHz, DMSO-d₆: δ 9.5 (bs, 1H), 7.55 (d, 2H), 7.05 (d, 2H), 7.0 (d, 2H), 6.75 (d, 2H), 3.8 (s, 3H), 1.4 (s, 6H). MS: [M+H]: m/z=311.2. HPLC: (98.8%, Eclipse XDB-C18, 150×4.6 mm, Sum. Mobile Phase: 0.1% TFA in Water. (A). ACN (B), Flow rate: 1.5 ml/min).

Synthesis of 5-(4-Hydroxyphenyl)-2,2-dimethyl-4-(pyridin-4-yl) furan-3(2H)-one Trimethyl (2-methylbut-3-yn-2-yloxy) silane

To a stirred solution of 2-methylbut-3-yn-2-ol (20 g, 0.23 mol) in HMDS (42.3 g, 0.261 mol) was added LiClO₄ (38.03 g, 0.35 mol) at RT. The reaction mixture was then stirred for additional 30 minutes, diluted with water (100 mL) and then extracted with ether (3×200 mL). The combined ether layers were washed with water (100 mL) and brine (100 mL), dried over Na₂SO and filtered. The ether was distilled off at 80° C. to afford trimethyl (2-methylbut-3-yn-2-yloxy) silane (25 g) as an oil.

4-Methyl-1-(pyridin-4-yl)-4-(trimethylsilyloxy) pent-2-yn-1-one

To a pre-cooled −78° C. stirred solution of trimethyl (2-methylbut-3-yn-2-yloxy) silane (5.0 g, 0.03 mol) in dry THF (150 mL), n-BuLi (23.82 mL, 0.03 mol, 1.6 M in hexane) was added dropwise over a period of 10 minutes under an inert atmosphere. The reactions was stirred for 30 minutes at −78° C. and then a solution of N-methoxy-N-methylisonicotinamide (6.34 g, 0.03 mol) in dry THF (30 mL) was added to the reaction mixture and stirring was continued for an additional 40 min at −78° C. The reaction mixture was quenched with a saturated NH₄Cl solution and extracted with EtOAc (2×100 mL). The combined organic layers were washed with water (100 mL) and brine (100 mL), dried over Na₂SO₄, filtered and finally concentrated in vacuo to obtain a residue. The residue was purified via silica gel column chromatography eluting with 5% EtOAc in hexanes to afford 4-methyl-1-(pyridin-4-yl)-4-(trimethylsilyloxy) pent-2-yn-1-one (2.2 g, 27%) as oil.

4-Hydroxy-4-methyl-1-(pyridin-4-yl) pent-2-yn-1-one

To a stirred solution of 4-methyl-1-(pyridin-4-yl)-4-(trimethylsilyloxy) pent-2-yn-1-one (0.5 g, 1.915 mmol) in DCM (10 mL) was added PTSA (0.47 g, 2.49 mmol) at RT and the reaction mixture was stirred for 2 h. The reaction mixture was diluted with DCM (50 mL). The organic layers were washed with a saturated NaHCO₃ solution and water, dried over Na₂SO₄, filtered and then concentrated in vacuo to afford 4-hydroxy-4-methyl-1-(pyridin-4-yl) pent-2-yn-1-one (0.35 g, 96%) as an oil.

2,2-Dimethyl-5-(pyridin-4-yl) furan-3(2H)-one

To a stirred solution of 4-hydroxy-4-methyl-1-(pyridin-4-yl) pent-2-yn-1-one (1.49 g, 0.007 mol) in ethanol (15 mL), diethylamine (0.511 g, 0.007 mol) in EtOH (15 mL) was added dropwise at RT. The mixture was then stirred for additional 40 min. The EtOH was evaporated and the mixture was diluted with EtOAc (100 mL). The organic layers were washed with water (50 mL) and brine (20 mL), dried over Na₂SO₄, filtered and concentrated in vacuo to afford 2,2-dimethyl-5-(pyridin-4-yl) furan-3(2H)-one (1.4 g).

4-Bromo-2,2-dimethyl-5-(pyridin-4-yl) furan-3(2H)-one

To a stirred solution of 2,2-dimethyl-5-(pyridin-4-yl) furan-3(2H)-one (0.81 g, 4.28 mmol) in CHCl₃ (20 mL), NBS (1.3 g, 7.28 mmol) was added portionwise at RT. The reaction mixture was then stirred for 2 h and diluted with DCM (100 mL). The organic layers were washed with water (50 mL) and brine (50 mL), dried over Na₂SO₄, filtered, and then concentrated in vacuo to obtain the crude product. The crude material was purified via silica gel column chromatography to afford 4-bromo-2,2-dimethyl-5-(pyridin-4-yl) furan-3(2H)-one (0.25 g, 21%) as a solid

4-(4-(Benzyloxy)phenyl)-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one

A solution of 4-bromo-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one (10.0 g, 37.2 mmol), 2-(4-(benzyloxy)phenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (13.8 g, 44.7 mmol), and Cs₂CO₃ (36.27 g, 111.6 mmol) in toluene (100 mL) and water (50 mL) was degassed. Dichloro[1,1′-bis(diphenylphosphino)ferrocene]palladium(11) (2.7 g, 3.7 mmol) was added under an inert atmosphere and again degassed. Then the reaction was refluxed for 3 h and monitored by TLC. Upon complete consumption of the starting material, the reaction mixture was filtered through a bed of Celite® washing with ethyl acetate. The organic layer was then washed with water, brine, dried over Na₂SO₄, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 20% ethyl acetate in n-hexanes on 230-400 mesh silica gel to afford 4-(4-(benzyloxy)phenyl)-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one (8.3 g, 60.2%) as a light orange color solid. ¹H NMR, 500 MHz, DMSO-d₆: δ 8.2 (d, 2H), 7.85 (d, 2H), 7.6 (d, 4H), 7.4 (t, 1H), 7.15 (d, 2H), 7.05 (d, 2H), 5.1 (s, 2H), 1.45 (s, 6H). MS: [M+H]+: m/z=396.0. HPLC: (97.5%, Column: Eclipse XDB-C18, 150×4.6 mm, 5 um. Mobile Phase: 0.1% TFA in Water. (A). ACN (B), Flow rate: 1.5 ml/min).

5-(4-Hydroxyphenyl)-2,2-dimethyl-4-(pyridin-4-yl) furan-3(2H)-one

To a stirred solution of 5-(4-(benzyloxy)phenyl)-2,2-dimethyl-4-(pyridin-4-yl) furan-3(2H)-one (620 mg, 0.001 mmol) in MeOH (15 mL) was added Pd (OH)₂ (120 mg, 0.85 mmol) at RT under an inert atmosphere. The reaction mixture was stirred under a hydrogen atmosphere for 1 h. The reaction mixture was then filtered through a pad of Celite® and the filtrate was concentrated in vacuo to obtain the crude product. The crude material was purified via silica gel column chromatography to afford 5-(4-hydroxyphenyl)-2,2-dimethyl-4-(pyridin-4-yl) furan-3(2H)-one (280 mg, 60%) as a solid.

Synthesis of 4-(3-(4-Hydroxyphenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile 4-Cyano-N-methoxy-N-methylbenzamide

To a stirred solution of 4-cyanobenzoic acid (5.0 g, 34.0 mmol) in DCM (75 mL) were added HATU (19.40 g, 51.0 mmol), N-methoxy, N-methylamine (4.90 g, 51.0 mmol) and TEA (14.30 mL, 102.0 mmol) at RT under a nitrogen atmosphere. The reaction mixture was then stirred at RT for 3 h, diluted with water and the aqueous layer was extracted with DCM (3×100 mL). The combined organic extracts were washed with water (60 mL) and brine (30 mL), dried over anhydrous Na₂SO₄, filtered and evaporated under reduced pressure to afford 4-cyano-N-methoxy-N-methylbenzamide (6.2 g, 96%) as a yellow color oil.

4-(4-Methyl-4-(trimethylsilyloxy) pent-2-ynoyl)benzonitrile

To a −78° C. stirred solution of trimethyl (2-methylbut-3-yn-2-yloxy) silane (3.3 g, 20.00 mmol) in dry THF (45 mL), n-BuLi (4.1 mL, 9.00 mmol, 1.6 M in hexane) was added dropwise over 10 minutes under an inert atmosphere. The reaction mixture was stirred for 30 min at −78° C., and then a solution of 4-cyano-N-methoxy-N-methylbenzamide (2.0 g, 10.00 mmol) in dry THF (15 mL) was added to the reaction mixture and stirring was continued for an additional 1 h at −78° C. The reaction mixture was quenched with a saturated NH₄Cl solution and extracted with EtOAc (2×100 mL). The combined organic layers were washed with water (50 mL) and brine (50 mL), dried over Na₂SO₄, filtered, and concentrated in vacuo to obtain the crude product. The crude material was purified via silica gel column chromatography eluting with 15% EtOAc in hexanes to afford 4-(4-methyl-4-(trimethylsilyloxy) pent-2-ynoyl)benzonitrile (3.8 g, 68%) as a yellow oil.

4-(4-Hydroxy-4-methylpent-2-ynoyl)benzonitrile

To a stirred solution of 4-(4-methyl-4-(trimethylsilyloxy) pent-2-ynoyl)benzonitrile (1.7 g, 5.00 mmol) in DCM (15 mL) was added PTSA (1.70 g, 8.90 mmol) at RT and the reaction mixture was stirred for 30 min. The reaction mixture was diluted with water (10 mL) and extracted with DCM (2×50 mL). The combined organic layers were washed with a saturated NaHCO₃ solution and water, dried over Na₂SO₄, filtered, and then concentrated in vacuo to afford 4-(4-hydroxy-4-methylpent-2-ynoyl)benzonitrile (1.20 g) as a yellow oil.

4-(5,5-Dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile

To a stirred solution of crude 4-(4-hydroxy-4-methylpent-2-ynoyl)benzonitrile (1.2 g, 5.60 mmol) in ethanol (12 mL), a solution of diethyl amine (0.58 mL, 5.60 mmol) in EtOH (5 mL) was added dropwise at RT. The reaction mixture was then stirred for additional 1 h. The ethanol was removed and the mixture then diluted with EtOAc (50 mL). The combined organic layers were washed with water (10 mL), brine (10 mL), dried over Na₂SO₄, filtered, and concentrated in vacuo to afford crude 4-(5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (1.2 g) as a light green semi solid which was taken on to the next step without further purification.

4-(3-Bromo-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile

To a stirred solution of 4-(5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (1.2 g, 5.60 mmol) in CHCl₃ (12 mL), NBS (1.1 g, 6.00 mmol) was added portionwise at RT. The reaction mixture was then stirred for 3 h and diluted with DCM (100 mL). The combined organic layers were washed with water (30 mL) and brine (30 mL), dried over Na₂SO₄, filtered, and then concentrated in vacuo to obtain the crude product. The crude material was purified via silica gel column chromatography to afford 4-(3-bromo-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (0.50 g, 31%) as an off white solid.

4-(3-(4-(benzyloxy)phenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile

A solution of 4-(3-bromo-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (29.0 g, 107.4 mmol), 2-(4-(benzyloxy)phenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (34.7 g, 118.8 mmol), and Cs₂CO₃ (104.7 g, 322.2 mmol) in toluene (200 mL) and water (50 mL) was degassed. Dichloro[1,1′-bis(diphenylphosphino)ferrocene]palladium(II) (8.5 g, 10 mmol) was added under an inert atmosphere and the solution was again degassed. The reaction was then refluxed for 3 h and monitored for completion by TLC. Upon complete consumption of the starting material, the reaction mixture was filtered through a bed of Celite® washing with ethyl acetate. The organic layer was then washed with water, brine, dried over Na₂SO₄, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 20% ethyl acetate in n-hexane on 230-400 mesh silica gel (Rf=0.3) to afford 4-(3-(4-(benzyloxy)phenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (31.5 g, 74.25%) as solid. ¹H NMR: 500 MHz, DMSO-d₆: δ 7.95 (d, 2H), 7.75 (d, 2H), 7.5 (d, 4H), 7.35 (t, 1H), 7.15 (d, 2H), 7.05 (d, 2H), 5.1 (s, 2H), 1.45 (s, 6H). MS: [M+H]+: m/z=396.0. HPLC: (99.5%, Eclipse XDB-C18, 150×4.6 mm, Sum. Mobile Phase: 0.1% TFA in Water. (A). ACN (B), Flow rate: 1.5 ml/min).

4-(3-(4-Hydroxyphenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile

Boron tribromide (3.4 g, 15.8 mmol) was added to a solution of 44344-(benzyloxy)phenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (2.5 g, 6.3 mmol) in DCM at 0° C. & the mixture was stirred for 1 h (reaction was monitored by TLC). Upon complete consumption of the starting material, the mixture was quenched with chilled water and extracted with DCM, The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by column chromatography to afford 4-(3-(4-hydroxyphenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (1.8 g, 93.2%,) as yellow solid. ¹H NMR: 500 MHz, CDCl₃: δ 9.6 (s, 1H), 7.95 (d, 2H), 7.75 (d, 2H), 7.0 (d, 2H), 6.75 (d, 2H), 1.5 (s, 6H).

2,3,5-Trimethylpyridine 1-oxide

3-Chloro per benzoic acid (10 g, 164.2 mmol) was added to a solution of 2,3,5-trimethylpyridine (10 g, 82.1 mmol) in DCM at 0° C. and the mixture was stirred at RT for 8 h (the reaction was monitored by TLC). The reaction was quenched with sodium bicarbonate solution and stirred for 1 h at RT. The organic layer was separated, dried over sodium sulfate, filtered and concentrated under reduced pressure to afford 2,3,5-trimethylpyridine 1-oxide (6.5 g, 58.0%,) as a brown solid. ¹H NMR: 200 MHz, CDCl₃: δ 8.15 (s, 1H), 7.15 (s, 1H), 2.55 (s, 3H), 2.35 (s, 3H), 2.25 (s, 3H). MS: [M+H]+: m/z=311.2.

2-(Chloromethyl)-3,5-dimethylpyridine

Tosyl chloride (12.5 g, 65.6 mmol) was added to a solution of 2,3,5-trimethylpyridine 1-oxide (6.0 g, 43.7 mmol), and triethylamine (6.6 g, 65.6 mmol) in DCM (60 ml) at RT under an atmosphere of nitrogen. The reaction mixture was heated to reflux and reflux was maintained 4 h (reaction was monitored by TLC). The reaction was quenched with water and extracted with DCM. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 10% ethyl acetate in n-hexanes and silica gel (230-400 Mesh) to afford 2-(chloromethyl)-3,5-dimethylpyridine (4.5 g, 66.1%,) as a brown thick syrup. ¹H NMR: 200 MHz, CDCl₃: δ 8.15 (s, 1H), 7.45 (s, 1H), 4.75 (s, 2H), 2.35 (s, 3H), 2.25 (s, 3H). MS: [M+H]+: m/z=156.3.

4-(4-((3,5-dimethylpyridin-2-yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one

4-(4-Hydroxyphenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (3.0 g, 9.6 mmol) was added to a mixture of cesium carbonate (12.6 g, 38.6 mmol) and DMF (1000 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 30 min upon which 2-(chloromethyl)-3,5-dimethylpyridine (2.25 g, 14.5 mmol) was added. The reaction mixture was heated for 4 h at 80° C. (the reaction was monitored by TLC). The reaction mixture was diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 15% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 4-(4-(3,5-dimethylpyridin-2-yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (3.2 g, 65.3%,) as an off-white solid. ¹H NMR: 500 MHz, DMSO-d₆: δ 8.2 (s, 1H), 7.65 (d, 2H), 7.45 (s, 1H), 7.15 (d, 2H), 7.1 (d, 2H), 7.0 (d, 2H), 5.2 (s, 2H), 3.8 (s, 3H), 2.35 (s, 3H), 2.3 (s, 3H), 1.45 (s, 6H). MS: [M+H]+: m/z=430.4. HPLC (96.3%, Condition-A).

4-(4-((3,5-dimethylpyridin-2-yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one methanesulfonate

Methanesulfonic acid (445.0 mg, 4.6 mmol) was added to a solution of 4-(4-((3,5-dimethylpyridin-2-yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (2.01 g, 4.6 mmol) in DCM (3 ml) and diethyl ether (150 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 4 h and the solids were removed by filtration. The solid was washed with 20% DCM in diethyl ether and dried under vacuo to afford 4-(4-((3,5-dimethylpyridin-2-yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one methanesulfonate (2.1 g, 87%) as a white solid. ¹H NMR: 500 MHz, DMSO-d₆: δ 8.2 (s, 1H), 7.65 (d, 2H), 7.45 (s, 1H), 7.15 (d, 2H), 7.1 (d, 2H), 7.0 (d, 2H), 5.2 (s, 2H), 3.8 (s, 3H), 2.35 (s, 3H), 2.3 (s, 3H), 1.45 (s, 6H), HPLC: (98.9%, Condition-A).

2-(Chloromethyl) imidazo[1,2-a]pyridine

1,3-Dichloroacetone (22.9 g, 180.3 mmol) was added to a solution of 2-amino pyridine (10 g, 106.3 mmol) in acetonitrile (200 ml). The mixture was heated at reflux for 14 h (the reaction was monitored by TLC). Upon completion of the reaction, the volatiles were removed under reduced pressure. The residue was diluted with water and adjusted the pH to 7.5 with sodium bicarbonate solution which was extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 12% ethyl acetate in n-hexanes and silica gel (230-400 mesh) to afford 2-(chloromethyl) imidazo[1,2-a]pyridine (8.0 g, 47.9%,) as pale yellow solid. ¹H NMR: 200 MHz, CDCl₃: δ 8.15 (d, 1H), 7.6 (dd, 2H), 7.1 (t, 1H), 6.8 (t, 1H), 4.75 (s, 2H). MS: [M+H]+: m/z=167.2.

4-(4-(Imidazo[1,2-a]pyridin-2-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one

4-(4-Hydroxyphenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (2.5 g, 8.06 mmol) was added to a mixture of cesium carbonate (10.5 g, 32.2 mmol) and DMF (20 mL) at RT under nitrogen. The reaction mixture was stirred at RT for 30 min, upon which 2-(chloromethyl) imidazo[1,2-a]pyridine (2.4 g, 12.0 mmol) was added. The mixture was heated at 80° C. for 4 h (reaction was monitored by TLC). The reaction mixture was allowed to cool to RT, diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 20% ethyl acetate in n-hexane and silica gel (230-400 mesh), to afford 4-(4-(imidazo[1,2-a]pyridin-2-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (2.8 g, 77.7%,) as Off-white solid. ¹H NMR: 500 MHz, DMSO-d₆: δ 8.55 (d, 1H), 8.0 (s, 1H), 7.55 (Ar, 3H), 7.3-6.85 (Ar, 8H), 5.15 (s, 2H) 3.85 (s, 3H), 1.25 (s, 6H). MS: [M+H]+: m/z=441.2. HPLC: (97.3%, Condition-A).

4-(4-(Imidazo[1,2-a]pyridin-2-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one methanesulfonate

Methanesulfonic acid (531 mg, 5.5 mmol) was added to a solution of 4-(4-(imidazo[1,2-a]pyridin-2-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (2.5 g, 5.5 mmol) in DCM (5 ml) and diethyl ether (150 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred for a further 4 h at RT. The solids were collected by filtration, washed with 20% DCM in diethyl ether and dried in vacuo to afford 4-(4-(imidazo[1,2-a]pyridin-2-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one methanesulfonate (2.4 g, 82.7%,) as white solid. ¹H NMR: 500 MHz, DMSO-d₆: δ 8.75 (d, 1H), 8.1 (s, 1H), 7.65 (Ar, 3H), 7.3-6.85 (Ar, 8H), 5.2 (s, 2H) 3.85 (s, 3H), 1.25 (s, 6H), HPLC: (98.8%, Condition-A).

6-Chloroimidazo[1,2-b]pyridazine

Bromoacetaldehyde diethylacetal (36.5 g, 216 mmol) was added to a solution of aq.cHBr (7.2 ml) and then heated to reflux for 30 min. The mixture was then cooled to 0° C., upon which ethanol (236 ml), sodium bicarbonate (8.09 g, 95 mmol) and 6-chloropyridazin-3-amine (4 g, 30 mmol) were added. The mixture was heated to 80° C. for 3 h (reaction was monitored by TLC) and then allowed to cool to RT. The mixture was concentrated under reduced pressure, diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 15% ethyl acetate in n-hexane and silica gel (230-400 mesh), to afford 6-chloroimidazo[1,2-b]pyridazine (4.0 g, 85.2%,) as Off-white solid. ¹H NMR: 200 MHz, CDCl₃: δ 7.4-7.2 (Ar, 4H), 3.85 (q, 1H), 3.4 (q, 1H), 3.2 (q, 2H), 1.35 (t, 3H), 1.1 (t, 3H). MS: [M+H]+: m/z=154.3.

Methylimidazo[1,2-b]pyridazine-6-carboxylate

6-Chloroimidazo[1,2-b]pyridazine (5.0 g, 32 mmol) was added to a solution of methanol (75 ml) and acetonitrile (75 ml) in a steel bomb at RT under nitrogen bubbling. Triethylamine (4.0 g, 39.4 mmol), BINAP (2.0 g, 3.0 mmol) and bisacetonitrile palladium dichloride (0.854 g, 3.0 mmol) were then added to the mixture. The mixture was heated to 100° C. which was maintained for approximately 10 hours (the reaction was monitored by TLC). The reaction mixture was filtered through a bed of Celite® washing with ethyl acetate. The organics were washed with water and brine, dried over sodium sulfate and concentrated under reduced pressure. The residue was purified by flash column chromatography using 10% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford methyl imidazo[1,2-b]pyridazine-6-carboxylate (2.5 g, 43%,) as an off-white solid. ¹H NMR: 200 MHz, DMSO-d₆₃: δ 8.55 (s, 1H), 8.3 (d, 1H), 7.95 (s, 1H), 7.55 (d, 1H), 3.95 (s, 3H). MS: [M+H]+: m/z=177.9.

Imidazo[1,2-b]pyridazin-6-ylmethanol

Sodium borohydride (1.1 g, 31.1 mmol) was added to a solution of methyl imidazo[1,2-b]pyridazine-6-carboxylate (2.4 g, 15.5 mmol) in THF (35 mL) and methanol (2.5 ml) at RT. The reaction mixture was stirred at RT for 2 h (the reaction was monitored by TLC) upon which the mixture was concentrated under reduced pressure. The reaction mixture was diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure to afford imidazo[1,2-b]pyridazin-6-ylmethanol (1.6 g, 81%,) as a white solid. ¹H NMR: 200 MHz, DMSO-d₆: δ 8.5 (s, 1H), 8.3 (d, 1H), 7.9 (s, 1H), 7.55 (d, 1H), 5.65 (t, 1H), 4.6 (d, 2H). MS: [M+H]+: m/z=311.2.

6-(Chloromethyl) imidazo[1,2-b]pyridazine

Thionyl chloride (10 ml) was added to imidazo[1,2-b]pyridazin-6-ylmethanol (1.5 g, 9.0 mmol) at 20° C. under an atmosphere of nitrogen at RT. The reaction mixture was stirred at reflux for 3 h (the reaction was monitored by TLC) upon which the volatiles were removed under reduced pressure. The reaction mixture was diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 15% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 6-(chloromethyl) imidazo[1,2-b]pyridazine (1.2 g, 69%,) as an off-white solid. ¹H NMR, 200 MHz, DMSO-d₆: δ 8.35 (s, 1H), 8.3 (d, 1H), 7.85 (s, 1H), 7.35 (d, 1H), 4.95 (s, 2H). MS: [M+H]+: m/z=149.9.

4-(4-(Imidazo[1,2-b]pyridazin-6-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one

4-(4-Hydroxyphenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (1.2 g, 3.8 mmol) was added to a mixture of cesium carbonate (3.7 g, 11.6 mmol) and DMF (25 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 30 min upon which 6-(chloromethyl) imidazo[1,2-b]pyridazine (0.96 g, 5 mmol) was added. The mixture was heated at 80° C. for 4 h (the reaction was monitored by TLC). The reaction mixture was diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 30% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 4-(4-(imidazo[1,2-b]pyridazin-6-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (0.8 g, 47%,) as Off-white solid. ¹H NMR: 200 MHz, DMSO-d₆: δ 8.35 (s, 1H), 8.2 (d, 1H), 7.8 (s, 1H), 7.55 (d, 2H), 7.4 (d, 1H), 7.2 (d, 2H), 7.1 (d, 2H), 7.0 (d, 2H), 5.3 (s, 2H) 3.9 (s, 3H), 1.45 (s, 6H). MS: [M+H]+: m/z=442.1. HPLC: (95.8%, Condition-A).

4-(4-(Imidazo[1,2-b]pyridazin-6-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one methanesulfonate

Methanesulfonic acid (54 mg, 0.5 mmol) was added to a solution of compound 4-(4-(imidazo[1,2-b]pyridazin-6-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (250 mg, 0.5 mmol) in DCM (2 ml) and diethyl ether (20 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 4 h upon which the mixture was filtered and the solids were washed with 20% DCM in diethyl ether and dried in vacuo to afford 4-(4-(imidazo[1,2-b]pyridazin-6-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one methanesulfonate (240 mg, 80.0%,) as an off-white solid. ¹H NMR: 200 MHz, DMSO-d₆: δ 8.55 (s, 1H), 8.35 (d, 1H), 78.1 (s, 1H), 7.65 (d, 2H), 7.4 (d, 1H), 7.2 (d, 2H), 7.1 (d, 2H), 7.0 (d, 2H), 5.35 (s, 2H) 3.9 (s, 3H), 2.35 (s, 3H), 1.45 (s, 6H). HPLC: (98.3%, Condition-A).

6-Chloro-2-(chloromethyl) imidazo[1,2-b]pyridazine

1,3-Dichloroacetone (21.4 g, 168.0 mmol) was added to a solution of 6-chloropyridazin-3-amine (10 g, 77.2 mmol) in acetonitrile (200 ml). The mixture was heated at reflux for 14 h (the reaction was monitored by TLC). The volatiles were removed under reduced pressure and the reaction mixture was diluted with water. The pH was adjusted to ˜7.5 with sodium bicarbonate solution and then extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 14% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 6-chloro-2-(chloromethyl) imidazo[1,2-b]pyridazine (6.0 g, 64.1%,) as white solid. ¹H NMR: 200 MHz, CDCl₃: δ 8.0 (s, 1H), 7.9 (d, 1H), 7.1 (d, 1H), 4.75 (s, 2H). MS: [M+H]+: m/z=202.8.

4-(4-((6-Chloroimidazo[1,2-b]pyridazin-2-yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one

4-(4-Hydroxyphenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (200 mg, 0.64 mmol) was added to a mixture of cesium carbonate (838 mg, 2.5 mmol) and DMF (5 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 30 min upon which 6-chloro-2-(chloromethyl) imidazo[1,2-b]pyridazine (196 mg, 9.6 mmol) was added. The mixture was heated at 80° C. for 4 h (the reaction was monitored by TLC). The reaction mixture was diluted with water and extracted with EtOAc; the combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The organic residue was purified by flash column chromatography using 30% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 4-(4-((6-chloroimidazo[1,2-b]pyridazin-2-yl) methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (180 mg, 63.0%,) as an off-white solid. ¹H NMR, 500 MHz, DMSO-d₆: δ 8.45 (s, 1H), 8.2 (d, 1H), 7.55 (d, 2H), 7.4 (d, 1H), 7.15 (d, 2H), 7.1 (d, 2H), 7.0 (d, 2H), 5.25 (s, 2H) 3.8 (s, 3H), 1.25 (s, 6H). MS: [M+H]+: m/z=476.7. HPLC: (96.7%, Condition-A).

4-(4-(Imidazo[1,2-b]pyridazin-2-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one

Palladium hydroxide (36 mg) was added to a solution of 4-(4-((6-chloroimidazo[1,2-b]pyridazin-2-yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (180 mg, 0.37 mmol) and diethyl amine (28 mg, 0.37) in methanol (25 ml) at RT under an atmosphere of nitrogen. The nitrogen atmosphere was exchanged for hydrogen and was stirred at RT for 2 h (the reaction was monitored by TLC). The compound was filtered through a bed of Celite® bed washing with methanol. The filtrate was concentrated under reduced pressure to afford 4-(4-(imidazo[1,2-b]pyridazin-2-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (160 mg, 96.7%,) as a white solid. ¹H NMR: 500 MHz, DMSO-d₆: δ 8.45 (s, 1H), 8.4 (s, 1H) 8.15 (d, 1H), 7.55 (d, 2H), 7.25 (d, 1H), 7.15 (d, 2H), 7.1 (d, 2H), 7.0 (d, 2H), 5.25 (s, 2H) 3.8 (s, 3H), 1.25 (s, 6H). MS: [M+H]+: m/z=442.3. HPLC: (97.4%, Condition-A).

4-(4-(Imidazo[1,2-b]pyridazin-2-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one methanesulfonate

Methanesulfonic acid (34.8 mg, 0.36 mmol) was added to a solution of compound 4-(4-(imidazo[1,2-b]pyridazin-2-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (160 mg, 0.36 mmol) in DCM (3 ml) and diethyl ether (15 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 4 h, upon which the mixture was filtered and the solids were washed with 20% DCM in diethyl ether. The solids were dried under vacuo to afford 4-(4-(imidazo[1,2-b]pyridazin-2-ylmethoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one methanesulfonate (110 mg, 56%,) as a white solid. ¹H NMR: 500 MHz, DMSO-d₆: δ 8.45 (s, 1H), 8.4 (s, 1H) 8.15 (d, 1H), 7.55 (d, 2H), 7.25 (d, 1H), 7.15 (d, 2H), 7.1 (d, 2H), 7.0 (d, 2H), 5.25 (s, 2H) 3.8 (s, 3H), 2.35 (s, 3H), 1.25 (s, 6H), HPLC: (98.5%, Condition-A).

4-(3-(4-((3,5-dimethylpyridin-2-yl)methoxy)phenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile

4-(3-(4-Hydroxyphenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (1.5 g, 4.9 mmol) was added to a mixture of carbonate (6.3 g, 19.6 mmol) and DMF (100 mL) at RT under nitrogen. The reaction mixture was stirred at RT for 30 min upon which 2-(chloromethyl)-3,5-dimethylpyridine (1.14 g, 7.3 mmol) was added. The mixture was heated at 80° C. for 4 h (the reaction was monitored by TLC). The reaction mixture was diluted with water and extracted with EtOAc; the combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 22% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 4-(3-(4-((3,5-dimethylpyridin-2-yl)methoxy)phenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl) (0.70 g, 35%,) as yellow solid. ¹H NMR, 200 MHz, CDCl₃: δ 7.45-6.8 (Ar, 11H), 4.9 (d, 1H), 4.6 (d, 1H), 3.75 (s, 3H), 3.2 (d, 2H) 3.1 (q, 1H), 2.5 (q, 1H) 0.95 (t, 6H). MS: [M+H]+: m/z=425.2. HPLC: (96.3%, Condition-A).

4-(3-(4-((3,5-Dimethylpyridin-2-yl)methoxy)phenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile methanesulfonate

Methanesulfonic acid (158 mg, 1.6 mmol) was added to a solution of compound 4-(3-(4-((3,5-dimethylpyridin-2-yl)methoxy)phenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl) (700 mg, 1.6 mmol) in DCM (0.5 ml) and diethyl ether (15 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 4 h upon which, the mixture was filtered and the solids were washed with 20% DCM in diethyl ether and dried in vacuo to afford 4-(3-(4-((3,5-dimethylpyridin-2-yl)methoxy)phenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile methanesulfonate (2.1 g, 75%,) as a white solid. ¹H NMR: 200 MHz, CDCl₃: δ 8.2 (d, 1H), 7.5 (t, 1H), 7.3-6.8 (Ar, 9H) 5.1 (s, 2H), 4.05 (s, 2H), 3.8 (s, 3H), HPLC: (97.1%, Condition-A).

4-(3-(4-(Imidazo[1,2-a]pyridin-2-ylmethoxy)phenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile

4-(3-(4-Hydroxyphenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (3.15 g, 10.3 mmol) was added to a mixture of cesium carbonate (13.4 g, 41.3 mmol) and DMF (100 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 30 min upon which 2-(chloromethyl) imidazo[1,2-a]pyridine (2.0 g, 12.3 mmol) was added. The mixture was heated at 80° C. for 4 h (the reaction was monitored by TLC). The reaction mixture was diluted with water and extracted with EtOAc, the combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 20% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 4-(3-(4-(imidazo[1,2-a]pyridin-2-ylmethoxy)phenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (2.7 g, 60%,) as an off-white solid. ¹H NMR: 500 MHz, DMSO-d₆: δ 8.55 (d, 1H), 8.0 (s, 1H), 7.55 (Ar, 3H), 7.3-6.85 (Ar, 8H), 5.15 (s, 2H), 1.25 (s, 6H). MS: [M+H]+: m/z=436.2. HPLC: (97.3%, Condition-A).

4-(3-(4-(Imidazo[1,2-a]pyridin-2-ylmethoxy)phenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile methanesulfonate

Methanesulfonic acid (309 mg, 3.2 mmol) was added to a solution of compound 4-(3-(4-(imidazo[1,2-a]pyridin-2-ylmethoxy)phenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (1.4 g, 3.2 mmol) in DCM (5 ml) and diethyl ether (30 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 4 h upon which it was filtered and the solids were washed with 20% DCM in diethyl ether and dried in vacuo to afford 4-(3-(4-(imidazo[1,2-a]pyridin-2-ylmethoxy)phenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile methanesulfonate (1.1 g, 64%,) as a white solid. ¹H NMR: 500 MHz, DMSO-d₆: δ 8.55 (d, 1H), 8.0 (s, 1H), 7.55 (Ar, 3H), 7.3-6.85 (Ar, 8H), 5.15 (s, 2H) 2.15 (s, 3H), 1.25 (s, 6H), HPLC: (98.5%, Condition-A).

3-Chloro-2-(chloromethyl)imidazo[1,2-a]pyridine

N-Chloro succinimide (329 g, 2.46 mmol) was added to a solution of 2-(chloromethyl)imidazo[1,2-a]pyridine (450 mg, 2.2 mmol) in DCM (15 ml) at RT under an atmosphere of nitrogen. Stirring was continued for 2 h (reaction was monitored by TLC) upon which the reaction mixture was diluted with DCM and washed with water and brine solution. The organic layer was dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 10% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 3-chloro-2-(chloromethyl) imidazo[1,2-a]pyridine (400 mg, 76%,) as Off-white solid. ¹H NMR: 200 MHz, CDCl₃: δ 8.4 (d, 1H), 7.7 (d, 1H), 7.5 (t, 1H), 7.1 (t, 1H), 4.85 (s, 2H). MS: [M+H]+: m/z=201.8. HPLC: (98.3%, Condition-A).

4-(4-((3-Chloroimidazo[1,2-a]pyridin-2-yl) methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one

4-(4-Hydroxyphenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (200 mg, 0.64 mmol) was added to a mixture of cesium carbonate (843 mg, 2.5 mmol) and DMF (20 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 30 min, upon which 3-chloro-2-(chloromethyl)imidazo[1,2-a]pyridine (183 mg, 0.77 mmol) was added. The mixture was heated at 80° C. for 4 h (the reaction was monitored by TLC) upon which, the mixture was diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 18% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 4-(4-((3-chloroimidazo[1,2-a]pyridin-2-yl) methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (250 mg, 81%,) as an off-white solid. ¹H NMR: 500 MHz, DMSO-d₆: δ 8.4 (d, 1H), 7.7 (d, 1H), 7.55 (Ar, 3H), 7.7-6.9 (Ar, 10H), 5.2 (s, 2H) 3.8 (s, 3H), 1.4 (s, 6H). MS: [M+H]+: m/z=470.7. HPLC: (97.2%, Condition-A).

4-(4-((3-Chloroimidazo[1,2-a]pyridin-2-yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one methanesulfonate

Methanesulfonic acid (50.5 mg, 0.52 mmol) was added to a solution of 4-(4-((3-chloroimidazo[1,2-a]pyridin-2-yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (250 mg, 0.52 mmol) in DCM (2.5 ml) and diethyl ether (25 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 4 h upon which the compound was filtered, washed with 20% DCM in diethyl ether and dried in vacuo to afford 4-(4-((3-chloroimidazo[1,2-a]pyridin-2-yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one methanesulfonate (260 mg, 86%,) as white solid. ¹H NMR: 500 MHz, δ 8.55 (d, 1H), 8.0 (s, 1H), 7.65 (Ar, 3H), 7.3-6.85 (Ar, 7H), 5.2 (s, 2H) 3.85 (s, 3H), 2.15 (s, 3H) 1.25 (s, 6H), HPLC: (98.8%, Condition-A).

Methyl 5-methylpicolinate

2-Chloro-5-methylpyridine (10 g, 78 mmol) was added to a solution of methanol (75 ml) and acetonitrile (75 ml) in steel bomb at RT under nitrogen bubbling followed by the addition of triethylamine (11.8 g, 117 mmol), BINAP (970 mg, 1.5 mmol) and bisacetonitrile palladium dichloride (0.4 g, 1.5 mmol). The mixture was heated to 100° C. and this temperature was maintained over night (the reaction was monitored by TLC). The reaction mixture was filter through Celite® bed and washing with ethyl acetate. The filtrate was washed with water and brine. The organic layer was concentrated under reduced pressure and purified by flash column chromatography using 10% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford methyl 5-methylpicolinate (6.5 g, 55%,) as an off-white solid. ¹H NMR: 200 MHz, CDCl₃: δ 8.6 (s, 1H), 8.0 (d, 1H), 7.65 (d, 1H), 4.05 (s, 3H), 2.4 (s, 3H). MS: [M+H]+: m/z=151.9.

(5-Methylpyridin-2-yl) methanol

Sodium borohydride (4.5 g, 115. mmol) was added to a solution of methyl 5-methylpicolinate (6.0 g, 39.5 mmol) in THF (60 mL) and methanol (6 ml) at RT. The reaction mixture was stirred at RT for 2 h (the reaction was monitored by TLC). The mixture was concentrated under reduced pressure and the residue was diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The organic layer was concentrated under vacuo to afford (5-methylpyridin-2-yl) methanol (3.5 g, 72.9%,) as an off-white solid. ¹H NMR: 200 MHz, CDCl₃: δ 8.5 (s, 1H), 7.7 (d, 1H), 7.15 (d, 1H), 5.0 (s, 3H), 3.4 (s, 3H). MS: [M+H]+: m/z=124.0.

2-(Chloromethyl)-5-methylpyridine

Thionyl chloride (30 ml) was added to (5-methylpyridin-2-yl) methanol (3.0 g, 24.3 mmol) at 20° C. under nitrogen. The reaction mixture was stirred at reflux for 3 h (the reaction was monitored by TLC). The reaction mixture was concentrated under reduced pressure upon which it was diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 6% ethyl acetate in n-hexane and silica gel (230-400 mesh), to afford 2-(chloromethyl)-5-methylpyridine (2.5 g, 73%,) as an off-white solid. ¹H NMR: 200 MHz, CDCl₃: δ 8.4 (s, 1H), 7.5 (d, 1H), 7.3 (d, 1H), 4.6 (s, 2H), 2.3 (s, 3H). MS: [M+H]+: m/z=142.2.

5-(4-Methoxyphenyl)-2,2-dimethyl-4-(4-((5-methylpyridin-2-yl)methoxy)phenyl)furan-3(2H)-one

4-(4-Hydroxyphenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (2.0, 6.5 mmol) was added to a mixture of cesium carbonate (10.5 g, 32.2 mmol) and DMF (50 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 30 min, upon which 2-(chloromethyl)-5-methylpyridine (1.36 g, 9.6 mmol) was added. The mixture was heated at 80° C. for 4 h (the reaction was monitored by TLC). The reaction mixture allowed to cool, diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 20% ethyl acetate in n-hexane and silica gel (230-400 mesh), to afford 5-(4-methoxyphenyl)-2,2-dimethyl-4-(4-((5-methylpyridin-2-yl)methoxy)phenyl)furan-3 (2H)-one (2.0 g, 76.9%,) as an off-white solid. ¹H NMR: 200 MHz, DMSO-d₆: δ 8.4 (s, 1H), 7.6 (d, 1H), 7.55 (d, 2H), 7.4 (d, 1H), 7.2 (d, 2H), 7.1 (d, 2H), 7.0 (d, 2H), 5.2 (s, 2H) 3.8 (s, 3H), 2.3 (s, 3H), 1.45 (s, 6H). MS: [M+H]+: m/z=415.2. HPLC: (97.5%, Condition-A).

5-(4-Methoxyphenyl)-2,2-dimethyl-4-(4-((5-methylpyridin-2-yl)methoxy)phenyl)furan-3(2H)-one methanesulfonate

Methanesulfonic acid (462 mg, 4.8 mmol) was added to a solution of 5-(4-methoxyphenyl)-2,2-dimethyl-4-(4-((5-methylpyridin-2-yl)methoxy)phenyl)furan-3(2H)-one (2.0 g, 4.8 mmol) in DCM (5 ml) and diethyl ether (50 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 4 h upon which the solids were collected by filtration, washed with 20% DCM in diethyl ether and dried in vacuo to afford 5-(4-Methoxyphenyl)-2,2-dimethyl-4-(4-((5-methylpyridin-2-yl)methoxy)phenyl)furan-3(2H)-one methanesulfonate (2.0 g, 90.9%,) as a white solid. ¹H NMR: 200 MHz, DMSO-d₆: δ 8.5 (s, 1H), 7.6 (d, 1H), 7.55 (d, 2H), 7.4 (d, 1H), 7.2 (d, 2H), 7.1 (d, 2H), 7.0 (d, 2H), 5.2 (s, 2H) 3.8 (s, 3H), 2.35 (s, 3H), 2.3 (s, 3H), 1.45 (s, 6H), HPLC: (99.3%, Condition-A).

4-(5,5-Dimethyl-3-(4-((5-methylpyridin-2-yl)methoxy)phenyl)-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile

4-(3-(4-Hydroxyphenyl)-5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (0.4 g, 1.3 mmol) was added to a mixture of cesium carbonate (1.7 g, 5.2 mmol) and DMF (20 mL) at RT under nitrogen. The reaction mixture was stirred at RT for 30 minutes upon which afford 2-(chloromethyl)-5-methylpyridine (306 mg, 1.9 mmol) was added. The mixture was heated at 80° C. for 4 h (the reaction was monitored by TLC). The reaction mixture was diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 25% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 4-(5,5-dimethyl-3-(4-((5-methylpyridin-2-yl)methoxy)phenyl)-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (160 mg, 30.1%,) as an off-white solid. ¹H NMR: 200 MHz, DMSO-d₆: δ 8.4 (s, 1H), 7.6 (d, 1H), 7.55 (d, 2H), 7.4 (d, 1H), 7.2 (d, 2H), 7.1 (d, 2H), 7.0 (d, 2H), 5.2 (s, 2H), 2.3 (s, 3H), 1.45 (s, 6H). MS: [M+H]+: m/z=411.2. HPLC: (97.3%, Condition-A).

4-(5,5-Dimethyl-3-(4-((5-methylpyridin-2-yl)methoxy)phenyl)-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile methanesulfonate

Methanesulfonic acid (36 mg, 0.3 mmol) was added to a solution of 4-(5,5-dimethyl-3-(4-((5-methylpyridin-2-yl)methoxy)phenyl)-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile (150 mg, 0.3 mmol) in DCM (5 ml) and diethyl ether (50 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 4 h upon which the solids were collected by filtration, washed with 20% DCM in diethyl ether, dried in vacuo to afford 4-(5,5-dimethyl-3-(4-((5-methylpyridin-2-yl)methoxy)phenyl)-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile methanesulfonate (120 mg, 67.0%,) as a white solid. ¹H NMR: 200 MHz, DMSO-d₆: δ 8.5 (s, 1H), 7.6 (d, 1H), 7.55 (d, 2H), 7.4 (d, 1H), 7.2 (d, 2H), 7.1 (d, 2H), 7.0 (d, 2H), 5.2 (s, 2H), 2.35 (s, 3H), 2.3 (s, 3H), 1.45 (s, 6H). HPLC: (98.3%, Condition-A).

Methyl 2-oxobutanoate

Trimethylsilyl chloride (1.06 g, 9.8 mmol) was added to a stirred solution of 2-oxobutanoic acid (10.0 g, 98.0 mmol) in 2,2-dimethoxypropane (90 ml) and methanol (20 ml). The mixture was stirred for 18 hours at RT (the reaction was monitored by TLC) upon which the mixture was concentrated under reduced pressure afford crude methyl 2-oxobutanoate (8.0 g) as a brown liquid. ¹H NMR: 200 MHz, CDCl₃: δ 3.85 (s, 3H), 2.9 (q, 2H), 1.15 (t, 1H), 6.8 (t, 1H), 4.75 (s, 2H).

Methyl 3-bromo-2-oxobutanoate

Copper bromide (30.0 g, 137 mmol) was added to a stirred solution of methyl 2-oxobutanoate (8.0 g, 68.9 mmol) in ethyl acetate (150 ml) and chloroform (100 ml). The mixture was stirred for 18 hours at reflux (the reaction was monitored by TLC). The mixture was filtered and washed with ethyl acetate and the filtrates were concentrated in vacuo to afford crude methyl 3-bromo-2-oxobutanoate (6.5 g) as a colorless liquid. ¹H NMR: 200 MHz, CDCl₃: δ 5.2 (q, 1H), 3.9 (s, 3H), 1.8 (d, 3H).

Methyl 3-methylimidazo[1,2-a]pyridine-2-carboxylate

Methyl 3-bromo-2-oxobutanoate (6.5 g, 34.3 mmol) was added to a stirred solution of 2-aminopyridine (4.0 g, 42.5 mmol) in acetonitrile (100 ml). The mixture was heated at reflux for 14 h (the reaction was monitored by TLC). The mixture was concentrated in vacuo and the residue was diluted with water and the pH was to 7.5 using sodium bicarbonate solution. The mixture was extracted with EtOAc; the combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 8% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford methyl 3-methylimidazo[1,2-a]pyridine-2-carboxylate (2.0 g, 25.1%,) as a pale yellow solid. ¹H NMR: 200 MHz, CDCl₃: δ 7.95 (d, 1H), 7.7 (d, 1H), 7.25 (t, 1H), 6.8 (t, 1H), 4.0 (s, 3H), 2.8 (s, 3H). MS: [M+H]+: m/z=191.1.

(3-Methylimidazo[1,2-a]pyridin-2-yl)methanol

Sodium borohydride (1.5 g, 41.6 mmol) was added to a solution of methyl 3-methylimidazo[1,2-a]pyridine-2-carboxylate (2.0 g, 10.5 mmol) in THF (50 mL) and methanol (2.5 ml) at RT. The reaction mixture was stirred at RT for 2 h (the reaction was monitored by TLC) upon which the mixture was concentrated under reduced pressure. The residue was diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure to afford (3-methylimidazo[1,2-a]pyridin-2-yl)methanol (0.8 g, 47.05%,) as off-white solid. ¹H NMR: 200 MHz, CDCl₃: δ 7.45 (d, 1H), 7.6 (d, 1H), 7.2 (t, 1H), 6.8 (t, 1H), 4.85 (s, 2H), 2.45 (s, 3H). MS: [M+H]+: m/z=162.9.

2-(Chloromethyl)-3-methylimidazo[1,2-a]pyridine

Thionyl chloride (10 ml) was added to (3-methylimidazo[1,2-a]pyridin-2-yl)methanol (0.8 g, 4.9 mmol) at 20° C. under an atmosphere of nitrogen. The reaction mixture was stirred at reflux for 3 h (the reaction was monitored by TLC). The mixture was concentrated under reduced pressure, the residue was diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 6% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 2-(chloroethyl)-3-methylimidazo[1,2-a]pyridine (400 mg, 45.4%,) as an off-white solid. ¹H NMR: 200 MHz, CDCl₃: δ 8.15 (s, 1H), 7.6 (s, 1H), 7.55 (d, 1H), 7.15 (d, 1H), 4.75 (s, 2H). MS: [M+H]+: m/z=181.3.

5-(4-Methoxyphenyl)-2,2-dimethyl-4-(4-((3-methylimidazo[1,2-a]pyridin-2-yl)methoxy)phenyl)furan-3(2H)-one

4-(4-Hydroxyphenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (0.1 g, 0.32 mmol) was added to a mixture of cesium carbonate (0.52 g, 1.62 mmol) and DMF (20 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 30 min upon which 2-(chloromethyl)-3-methylimidazo[1,2-a]pyridine (87 mg, 0.48 mmol) was added. The mixture was heated at for 4 h (the reaction was monitored by TLC). The reaction mixture was diluted with water and extracted with EtOAc, the combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 20% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 5-(4-methoxyphenyl)-2,2-dimethyl-4-(4-((3-methylimidazo[1,2-a]pyridin-2-yl)methoxy)phenyl)furan-3(2H)-one (2.8 g, 77%,) as an off-white solid. ¹H NMR, 500 MHz, DMSO-d₆: δ 8.25 (d, 1H), 7.45 (d, 3H), 7.25 (t, 1H), 7.15-6.95 (Ar, 7H), 5.2 (s, 2H), 3.85 (s, 3H), 2.45 (s, 3H), 1.45 (s, 6H). MS: [M+H]+: m/z=455.3. HPLC: (96.3%, Condition-A).

2-(Chloromethyl)-5-methylimidazo[1,2-a]pyridine

1,3-Dichloroacetone (17.6 g, 138.3 mmol) was added to a solution of 6-methylpyridin-2-amine (10 g, 92.5 mmol) in acetonitrile (200 ml). The mixture was heated at reflux for 14 h (the reaction was monitored by TLC). The mixture was concentrated under reduced pressure, the residue was diluted with water, and the pH was adjusted to 7.5 with sodium bicarbonate solution. The mixture was extracted with EtOAc, the combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 10% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 2-(chloromethyl)-5-methylimidazo[1,2-a]pyridine (7.0 g, 70.7%,) as a pale yellow solid. ¹H NMR: 200 MHz, CDCl₃: δ 8.15 (s, 1H), 7.6 (dd, 2H), 7.1 (t, 1H), 6.8 (t, 1H), 4.95 (s, 2H), 2.6 (s, 3H). MS: [M+H]+: m/z=181.5.

5-(4-Methoxyphenyl)-2,2-dimethyl-4-(4-((5-methylimidazo[1,2-a]pyridin-2-yl)methoxy)phenyl)furan-3(2H)-one

4-(4-Hydroxyphenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (250 mg, 0.8 mmol) was added to a mixture of cesium carbonate (1.05 g, 3.22 mmol) and DMF (20 mL) at RT under nitrogen. The reaction mixture was stirred at RT for 30 minutes upon which 2-(chloromethyl)-5-methylimidazo[1,2-a]pyridine (218 mg, 1.2 mmol) was added. The mixture was heated at for 4 h (the reaction was monitored by TLC) upon which the reaction mixture was diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 15% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 5-(4-methoxyphenyl)-2,2-dimethyl-4-(4-((5-methylimidazo[1,2-a]pyridin-2-yl)methoxy)phenyl)furan-3(2H)-one (280 mg, 77.7%,) as a light yellow solid. ¹H NMR: 500 MHz, DMSO-d₆: δ 7.95 (s, 1H), 7.6 (d, 2H), 7.4 (d, 1H), 7.25 (t, 1H), 7.2 (d, 3H), 7.15 (d, 2H), 7.0 (d, 2H), 6.8 (d, 1H), 5.2 (s, 2H) 3.85 (s, 3H), 2.6 (s, 3H), 1.25 (s, 6H). MS: [M+H]+: m/z=455.6. HPLC: (97.3%, Condition-A).

5-(4-Methoxyphenyl)-2,2-dimethyl-4-(4-((5-methylimidazo[1,2-a]pyridin-2-yl)methoxy)phenyl)furan-3(2H)-one methanesulfonate

Methanesulfonic acid (53.1 mg, 0.5 mmol) was added to a solution of 5-(4-methoxyphenyl)-2,2-dimethyl-4-(4-((5-methylimidazo[1,2-a]pyridin-2-yl)methoxy)phenyl)furan-3(2H)-one (250 g, 0.5 mmol) in DCM (2.5 ml) and diethyl ether (50 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 4 h upon which, the solids were collected by filtration, washed with 20% DCM in diethyl ether, dried in vacuo to afford 5-(4-methoxyphenyl)-2,2-dimethyl-4-(4-((5-methylimidazo[1,2-a]pyridin-2-yl)methoxy)phenyl)furan-3(2H)-one methanesulfonate (240 mg, 82.7%,) as white solid. ¹H NMR: 500 MHz, DMSO-d₆: δ 7.95 (s, 1H), 7.6 (d, 2H), 7.4 (d, 1H), 7.25 (t, 1H), 7.2 (d, 3H), 7.15 (d, 2H), 7.0 (d, 2H), 6.8 (d, 1H), 5.2 (s, 2H) 3.85 (s, 3H), 2.6 (s, 3H), 2.5 (s, 3H), 1.25 (s, 6H), HPLC: (98.4%, Condition-A).

6-Chloro-2-(chloromethyl)imidazo[1,2-a]pyridine

1,3-Dichloroacetone (7.4 g, 58.3 mmol) was added to a solution of 5-chloropyridin-2-amine (5.0 g, 38.9 mmol) in acetonitrile (100 ml). The mixture was heated at reflux for 14 h (the reaction was monitored by TLC). Upon completion of the reaction as judged by TLC, the mixture was concentrated under reduced pressure. The residue was diluted with water and the pH was adjusted to 7.5 with sodium bicarbonate solution. The mixture was extracted with EtOAc, the combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 10% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 6-chloro-2-(chloromethyl) imidazo[1,2-a]pyridine (1.5 g, 30%,) as a pale yellow solid. ¹H NMR: 200 MHz, CDCl₃: δ 8.0 (d, 1H), 7.6 (dd, 2H), 6.8 (d, 1H), 4.75 (s, 2H). MS: [M+H]+: m/z=201.9.

4-(4-((6-Chloroimidazo[1,2-a]pyridin-2-yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one

4-(4-Hydroxyphenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (300 mg, 0.96 mmol) was added to a mixture of cesium carbonate (1.05 g, 3.8 mmol) and DMF (20 mL) at RT under nitrogen. The reaction mixture was stirred at RT for 30 minutes, upon which 6-chloro-2-(chloromethyl)imidazo[1,2-a]pyridine (201 mg, 1.4 mmol) was added. The mixture was heated at 80° C. for 4 h (the reaction was monitored by TLC). Upon completion of the reaction as judged by TLC, the reaction mixture was diluted with water and extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 20% ethyl acetate in n-hexane and silica gel (230-400 mesh) to afford 4-(4-((6-chloroimidazo[1,2-a]pyridin-2-yl) methoxy)phenyl)-5-(4-methoxy phenyl)-2,2-dimethylfuran-3(2H)-one (180 mg, 39.3%,) as a white solid. ¹H NMR, 500 MHz, DMSO-d₆: δ 8.85 (s, 1H), 8.0 (s, 1H), 7.6 (d, 3H), 7.3 (d, 1H), 7.15 (d, 2H), 7.1 (d, 2H), 7.0 (d, 2H), 5.15 (s, 2H) 3.8 (s, 3H), 1.4 (s, 6H). MS: [M+H]+: m/z=475. HPLC: (98.0%, Condition-A).

4-(4-((6-Chloroimidazo[1,2-a]pyridin-2-yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one methanesulfonate

Methanesulfonic acid (53.1 mg, 0.5 mmol) was added to a solution of compound 4-(4-((6-chloroimidazo[1,2-a]pyridin-2-yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one (250 g, 0.5 mmol) in DCM (2.5 ml) and diethyl ether (50 mL) at RT under an atmosphere of nitrogen. The reaction mixture was stirred at RT for 4 h upon which the solids were collected by filtration, washed with 20% DCM in diethyl ether and dried in vacuo to afford 4-(4-((6-chloroimidazo[1,2-a]pyridin-2-yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one methanesulfonate (240 mg, 82%,) as a white solid. ¹H NMR: 500 MHz, DMSO-d₆: δ 8.8 (s, 1H), 8.3 (s, 1H), 8.0 (s, 1H), 7.6 (d, 2H), 7.4 (d, 1H), 7.15 (d, 2H), 7.1 (d, 2H), 7.0 (d, 2H) 5.35 (s, 2H), 3.8 (s, 3H), 2.3 (s, 3H), 1.4 (s, 6H), HPLC: (99.3%, Condition-A).

Tables

In the following tables, if a specific example contains multiple instances of R₂, they will be separated by commas in the table (e.g. Me, Me or Et, Me). If the R₂ column contains a value “-group-” e.g. “-cyclopropyl-”, then both R₂ values are taken together to be a spiro ring.

In a further aspect the compounds of the disclosure are embodied in with distinct examples listed in the table below taken from Formula (I):

Example # HET X Z R₂ 1 A29

Me, Me 2 A29

Me, Me 3 A29

Me, Me 4 A29

Me, Me 5 A29

Me, Me 6 A29

Me, Me 7 A29

Me, Me 8 A29

Me, Me 9 A29

Me, Me 10 A29

Me, Me 11 A29

Me, Me 12 A29

Me, Me 13 A29

Me, Me 14 A29

Me, Me 15 A29

Me, Me 16 A29

Me, Me 17 A29

Me, Me 18 A29

Me, Me 19 A29

Me, Me 20 A29

Me, Me 21 A29

Me, Me 22 A29

Me, Me 23 A29

Me, Me 24 A29

Me, Me 25 A29

Me, Me 26 A29

Me, Me 27 A29

Me, Me 28 A29

Me, Me 29 A29

Me, Me 30 A29

Me, Me 31 A29

Me, Me 32 A29

Me, Me 33 A29

Me, Me 34 A29

Me, Me 35 A29

Me, Me 36 A29

Me, Me 37 A29

Me, Me 38 A29

Me, Me 39 A29

Me, Me 40 A29

Me, Me 41 A29

Me, Me 42 A29

Me, Me 43 A29

Me, Me 44 A29

Me, Me 45 A29

Me, Me 46 A29

Me, Me 47 A29

Me, Me 48 A29

Me, Me 49 A29

Me, Me 50 A29

Me, Me 51 A29

Me, Me 52 A29

Me, Me 53 A29

Me, Me 54 A29

Me, Me 55 A29

Me, Me 56 A29

Me, Me 57 A29

Me, Me 58 A29

Me, Me 59 A29

Me, Me 60 A29

Me, Me 61 A29

Me, Me 62 A29

Me, Me 63 A29

Me, Me 64 A29

Me, Me 65 A29

Me, Me 66 A29

Me, Me 67 A29

Me, Me 68 A29

Me, Me 69 A29

Me, Me 70 A29

Me, Me 71 A29

Me, Me 72 A29

Me, Me 73 A29

Me, Me 74 A29

Me, Me 75 A29

Me, Me 76 A29

Me, Me 77 A29

Me, Me 78 A29

Me, Me 79 A29

Me, Me 80 A29

Me, Me 81 A29

Me, Me 82 A29

Me, Me 83 A29

Me, Me 84 A29

Me, Me 85 A29

Me, Me 86 A29

Me, Me 87 A29

Me, Me 88 A29

Me, Me 89 A29

Me, Me 90 A29

Me, Me 91 A29

Me, Me 92 A29

Me, Me 93 A29

Me, Me 94 A29

Me, Me 95 A29

Me, Me 96 A29

Me, Me 97 A29

Me, Me 98 A29

Me, Me 99 A29

Me, Me 100 A29

Me, Me 101 A29

Me, Me 102 A29

Me, Me 103 A29

Me, Me 104 A29

Me, Me 105 A29

Me, Me 106 A29

Me, Me 107 A29

Me, Me 108 A29

Me, Me 109 A29

Me, Me 110 A29

Me, Me 111 A29

Me, Me 121 A29

Me, Me 122 A29

Me, Me 123 A29

Me, Me 124 A29

Me, Me 125 A29

Me, Me 126 A29

Me, Me 127 A29

Me, Me 128 A29

Me, Me 129 A29

Me, Me 130 A29

Me, Me 131 A29

Me, Me 132 A29

Me, Me 133 A29

Me, Me 134 A29

Me, Me 135 A29

Me, Me 136 A29

Me, Me 137 A29

Me, Me 138 A29

Me, Me 139 A29

Me, Me 140 A29

Me, Me 141 A29

Me, Me 142 A29

Me, Me 143 A29

Me, Me 144 A29

Me, Me 145 A29

Me, Me 146 A29

Me, Me 147 A29

Me, Me 148 A29

Me, Me 149 A29

Me, Me 150 A29

Me, Me 151 A29

Me, Me 152 A29

Me, Me 153 A29

Me, Me 154 A29

Me, Me 155 A29

Me, Me 156 A29

Me, Me 157 A29

Me, Me 158 A29

Me, Me 159 A29

Me, Me 160 A29

Me, Me 161 A29

Me, Me 162 A29

Me, Me 163 A29

Me, Me 164 A29

Me, Me 165 A29

Me, Me 166 A29

Me, Me 167 A29

Me, Me 168 A29

Me, Me 169 A29

Me, Me 170 A29

Me, Me 171 A29

Me, Me 172 A29

Me, Me 173 A29

Me, Me 174 A29

Me, Me 175 A29

Me, Me 176 A29

Me, Me 177 A29

Me, Me 178 A29

Me, Me 179 A29

Me, Me 180 A29

Me, Me 181 A29

Me, Me 182 A29

Me, Me 183 A29

Me, Me 184 A29

Me, Me 185 A29

Me, Me 186 A29

Me, Me 187 A29

Me, Me 188 A29

Me, Me 189 A29

Me, Me 190 A29

Me, Me 191 A29

Me, Me 192 A29

Me, Me 193 A29

Me, Me 194 A29

Me, Me 195 A29

Me, Me 196 A29

Me, Me 197 A29

Me, Me 198 A29

Me, Me 199 A29

Me, Me 200 A29

Me, Me 201 A29

Me, Me 202 A29

Me, Me 203 A29

Me, Me 204 A29

Me, Me 205 A29

Me, Me 206 A29

Me, Me 207 A29

Me, Me 211 A29

Me, Me 212 A29

Me, Me 213 A29

Me, Me 214 A29

Me, Me 215 A29

Me, Me 216 A29

Me, Me 217 A29

Me, Me 218 A29

Me, Me 219 A29

Me, Me 220 A29

Me, Me 221 A29

Me, Me 222 A29

Me, Me 223 A29

Me, Me 224 A29

Me, Me 225 A29

Me, Me 226 A29

Me, Me 227 A29

Me, Me 228 A29

Me, Me 229 A29

Me, Me 230 A29

Me, Me 231 A29

Me, Me 232 A29

Me, Me 233 A29

Me, Me 234 A29

Me, Me 235 A29

Me, Me 236 A29

Me, Me 237 A29

Me, Me 238 A29

Me, Me 239 A29

Me, Me 240 A29

Me, Me 241 A29

Me, Me 242 A29

Me, Me 243 A29

Me, Me 244 A29

Me, Me 245 A29

Me, Me 246 A29

Me, Me 247 A29

Me, Me 248 A29

Me, Me 249 A29

Me, Me 250 A29

Me, Me 251 A29

Me, Me 252 A29

Me, Me 253 A31

Me, Me 254 A31

Me, Me 255 A31

Me, Me 256 A31

Me, Me 257 A31

Me, Me 258 A31

Me, Me 259 A31

Me, Me 260 A31

Me, Me 261 A31

Me, Me 262 A31

Me, Me 263 A31

Me, Me 264 A31

Me, Me 265 A31

Me, Me 266 A31

Me, Me 267 A31

Me, Me 268 A31

Me, Me 269 A31

Me, Me 270 A31

Me, Me 271 A31

Me, Me 272 A31

Me, Me 273 A31

Me, Me 274 A31

Me, Me 275 A31

Me, Me 276 A31

Me, Me 277 A31

Me, Me 278 A31

Me, Me 279 A31

Me, Me 280 A31

Me, Me 281 A31

Me, Me 282 A31

Me, Me 283 A31

Me, Me 284 A31

Me, Me 285 A31

Me, Me 286 A31

Me, Me 287 A31

Me, Me 288 A31

Me, Me 289 A31

Me, Me 290 A31

Me, Me 291 A31

Me, Me 292 A31

Me, Me 293 A31

Me, Me 294 A31

Me, Me 295 A31

Me, Me 296 A31

Me, Me 297 A31

Me, Me 298 A31

Me, Me 299 A31

Me, Me 300 A31

Me, Me 301 A31

Me, Me 302 A31

Me, Me 303 A31

Me, Me 304 A31

Me, Me 305 A31

Me, Me 306 A31

Me, Me 307 A31

Me, Me 308 A31

Me, Me 309 A31

Me, Me 310 A31

Me, Me 311 A31

Me, Me 312 A31

Me, Me 313 A31

Me, Me 314 A31

Me, Me 315 A31

Me, Me 316 A31

Me, Me 317 A31

Me, Me 318 A31

Me, Me 319 A31

Me, Me 320 A31

Me, Me 321 A31

Me, Me 322 A31

Me, Me 323 A31

Me, Me 324 A31

Me, Me 325 A31

Me, Me 326 A31

Me, Me 327 A31

Me, Me 328 A31

Me, Me 329 A31

Me, Me 330 A31

Me, Me 331 A31

Me, Me 332 A31

Me, Me 333 A31

Me, Me 334 A31

Me, Me 335 A31

Me, Me 336 A31

Me, Me 337 A31

Me, Me 338 A31

Me, Me 339 A31

Me, Me 340 A31

Me 341 A31

Me, Me 342 A31

Me, Me 343 A31

Me, Me 344 A31

Me, Me 345 A31

Me, Me 346 A31

Me, Me 347 A31

Me, Me 348 A31

Me, Me 349 A31

Me, Me 350 A31

Me, Me 351 A31

Me, Me 352 A31

Me, Me 353 A31

Me, Me 354 A31

Me, Me 355 A31

Me, Me 356 A31

Me, Me 357 A31

Me, Me 358 A31

Me, Me 359 A31

Me, Me 360 A31

Me, Me 361 A31

Me, Me 362 A31

Me, Me 363 A31

Me, Me 364 A31

Me, Me 365 A31

Me, Me 366 A31

Me, Me 367 A31

Me, Me 368 A31

Me, Me 369 A31

Me, Me 370 A31

Me, Me 371 A31

Me, Me 372 A31

Me, Me 373 A31

Me, Me 374 A31

Me, Me 375 A31

Me, Me 376 A31

Me, Me 377 A31

Me, Me 378 A31

Me, Me 379 A31

Me, Me 380 A31

Me, Me 381 A31

Me, Me 382 A31

Me, Me 383 A31

Me, Me 384 A31

Me, Me 385 A31

Me, Me 386 A31

Me, Me 387 A31

Me, Me 388 A31

Me, Me 389 A31

Me, Me 390 A31

Me, Me 391 A31

Me, Me 392 A31

Me, Me 393 A31

Me, Me 394 A31

Me, Me 395 A31

Me, Me 396 A31

Me, Me 397 A31

Me, Me 398 A31

Me, Me 399 A31

Me, Me 400 A31

Me, Me 401 A31

Me, Me 402 A31

Me, Me 403 A31

Me, Me 404 A31

Me, Me 405 A31

Me, Me 406 A31

Me, Me 407 A31

Me, Me 408 A31

Me, Me 409 A31

Me, Me 410 A31

Me, Me 411 A31

Me, Me 412 A31

Me, Me 413 A31

Me, Me 414 A31

Me, Me 415 A31

Me, Me 416 A31

Me, Me 417 A31

Me, Me 418 A31

Me, Me 419 A31

Me, Me 420 A31

Me, Me 421 A31

Me, Me 422 A31

Me, Me 423 A31

Me, Me 424 A31

Me, Me 425 A31

Me, Me 426 A31

Me, Me 427 A31

Me, Me 428 A31

Me, Me 429 A31

Me, Me 430 A31

Me, Me 431 A31

Me, Me 432 A31

Me, Me 433 A31

Me, Me 434 A31

Me, Me 435 A31

Me, Me 436 A31

Me, Me 437 A31

Me, Me 438 A31

Me, Me 439 A31

Me, Me 440 A31

Me, Me 441 A31

Me, Me 442 A31

Me, Me 443 A31

Me, Me 444 A31

Me, Me 445 A31

Me, Me 446 A31

Me, Me 447 A31

Me, Me 448 A31

Me, Me 449 A31

Me, Me 450 A31

Me, Me 451 A31

Me, Me 452 A31

Me, Me 453 A31

Me, Me 454 A31

Me, Me 455 A31

Me, Me 456 A31

Me, Me 457 A31

Me, Me 458 A31

Me, Me 459 A31

Me, Me 460 A31

Me, Me 461 A31

Me, Me 462 A31

Me, Me 463 A31

Me, Me 464 A31

Me, Me 465 A31

Me, Me 466 A31

Me, Me 467 A31

Me, Me 468 A31

Me, Me 469 A31

Me, Me 470 A31

Me, Me 471 A31

Me, Me 472 A31

Me, Me 473 A31

Me, Me 474 A31

Me, Me 475 A31

Me, Me 476 A31

Me, Me 477 A31

Me, Me 478 A31

Me, Me 479 A31

Me, Me 480 A31

Me, Me 481 A31

Me, Me 482 A31

Me, Me 483 A31

Me, Me 484 A31

Me, Me 485 A31

Me, Me 486 A31

Me, Me 487 A31

Me, Me 488 A31

Me, Me 489 A31

Me, Me 490 A31

Me, Me 491 A31

Me, Me 492 A31

Me, Me 493 A29

--cyclopropyl-- 494 A29

--cyclopropyl-- 495 A29

--cyclopropyl-- 496 A29

--cyclopropyl-- 497 A29

--cyclopropyl-- 498 A29

--cyclopropyl-- 499 A29

--cyclopropyl-- 500 A29

--cyclopropyl-- 501 A29

--cyclopropyl-- 502 A29

--cyclopropyl-- 503 A29

--cyclopropyl-- 504 A29

--cyclopropyl-- 505 A29

--cyclopropyl-- 506 A29

--cyclopropyl-- 507 A29

--cyclopropyl-- 508 A29

--cyclopropyl-- 509 A29

--cyclopropyl-- 510 A29

--cyclopropyl-- 511 A29

--cyclopropyl-- 512 A29

--cyclopropyl- 513 A29

--cyclopropyl-- 514 A29

--cyclopropyl-- 515 A29

--cyclopropyl-- 516 A29

--cyclopropyl-- 517 A29

--cyclopropyl-- 518 A29

--cyclopropyl-- 519 A29

--cyclopropyl-- 520 A29

--cyclopropyl-- 521 A29

--cyclopropyl-- 522 A29

--cyclopropyl-- 523 A29

--cyclopropyl-- 524 A29

--cyclopropyl-- 525 A29

--cyclopropyl-- 526 A29

--cyclopropyl-- 527 A29

--cyclopropyl-- 528 A29

--cyclopropyl-- 529 A29

--cyclopropyl-- 530 A29

--cyclopropyl-- 531 A29

--cyclopropyl-- 532 A29

--cyclopropyl-- 533 A29

--cyclopropyl-- 534 A29

--cyclopropyl-- 535 A29

--cyclopropyl-- 536 A29

--cyclopropyl-- 537 A29

--cyclopropyl-- 538 A29

--cyclopropyl-- 539 A29

--cyclopropyl-- 540 A29

--cyclopropyl-- 541 A29

--cyclopropyl-- 542 A29

--cyclopropyl-- 543 A29

--cyclopropyl-- 544 A29

--cyclopropyl-- 545 A29

--cyclopropyl-- 546 A29

--cyclopropyl-- 547 A29

--cyclopropyl-- 548 A29

--cyclopropyl-- 549 A29

--cyclopropyl-- 550 A29

--cyclopropyl-- 551 A29

--cyclopropyl-- 552 A29

--cyclopropyl-- 553 A29

--cyclopropyl-- 554 A29

--cyclopropyl-- 555 A29

--cyclopropyl-- 556 A29

--cyclopropyl-- 557 A29

--cyclopropyl-- 558 A29

--cyclopropyl-- 559 A29

--cyclopropyl-- 560 A29

--cyclopropyl-- 561 A29

--cyclopropyl-- 562 A29

--cyclopropyl-- 563 A29

--cyclopropyl-- 564 A29

--cyclopropyl-- 565 A29

--cyclopropyl-- 566 A29

--cyclopropyl-- 567 A29

--cyclopropyl-- 568 A29

--cyclopropyl-- 569 A29

--cyclopropyl-- 570 A29

--cyclopropyl-- 571 A29

--cyclopropyl-- 572 A29

--cyclopropyl-- 573 A29

--cyclopropyl-- 574 A29

--cyclopropyl-- 575 A29

--cyclopropyl-- 576 A29

--cyclopropyl-- 577 A29

--cyclopropyl-- 578 A29

--cyclopropyl-- 579 A29

--cyclopropyl-- 580 A29

--cyclopropyl-- 581 A29

--cyclopropyl-- 582 A29

--cyclopropyl-- 583 A29

--cyclopropyl-- 584 A29

--cyclopropyl-- 585 A29

--cyclopropyl-- 586 A29

--cyclopropyl-- 587 A29

--cyclopropyl-- 588 A29

--cyclopropyl-- 589 A29

--cyclopropyl-- 590 A29

--cyclopropyl-- 591 A29

--cyclopropyl-- 592 A29

--cyclopropyl-- 593 A29

--cyclopropyl-- 594 A29

--cyclopropyl-- 595 A29

--cyclopropyl-- 596 A29

--cyclopropyl-- 597 A29

--cyclopropyl-- 598 A29

--cyclopropyl-- 599 A29

--cyclopropyl-- 600 A29

--cyclopropyl-- 601 A29

--cyclopropyl-- 602 A29

--cyclopropyl-- 603 A29

--cyclopropyl-- 604 A29

--cyclopropyl-- 605 A29

--cyclopropyl-- 606 A29

--cyclopropyl-- 607 A29

--cyclopropyl-- 608 A29

--cyclopropyl-- 609 A29

--cyclopropyl-- 610 A29

--cyclopropyl-- 611 A29

--cyclopropyl-- 612 A29

--cyclopropyl-- 613 A29

--cyclopropyl-- 614 A29

--cyclopropyl-- 615 A29

--cyclopropyl-- 616 A29

--cyclopropyl-- 617 A29

--cyclopropyl-- 618 A29

--cyclopropyl-- 619 A29

--cyclopropyl-- 620 A29

--cyclopropyl-- 621 A29

--cyclopropyl-- 622 A29

--cyclopropyl-- 623 A29

--cyclopropyl-- 624 A29

--cyclopropyl-- 625 A29

--cyclopropyl-- 626 A29

--cyclopropyl-- 627 A29

--cyclopropyl-- 628 A29

--cyclopropyl-- 629 A29

--cyclopropyl-- 630 A29

--cyclopropyl-- 631 A29

--cyclopropyl-- 632 A29

--cyclopropyl-- 633 A29

--cyclopropyl-- 634 A29

--cyclopropyl-- 635 A29

--cyclopropyl-- 636 A29

--cyclopropyl-- 637 A29

--cyclopropyl-- 638 A29

--cyclopropyl-- 639 A29

--cyclopropyl-- 640 A29

--cyclopropyl-- 641 A29

--cyclopropyl-- 642 A29

--cyclopropyl-- 643 A29

--cyclopropyl-- 644 A29

--cyclopropyl- 645 A29

--cyclopropyl-- 646 A29

--cyclopropyl-- 647 A29

--cyclopropyl-- 648 A29

--cyclopropyl-- 649 A29

--cyclopropyl-- 650 A29

--cyclopropyl-- 651 A29

--cyclopropyl-- 652 A29

--cyclopropyl-- 653 A29

--cyclopropyl-- 654 A29

--cyclopropyl-- 655 A29

--cyclopropyl-- 656 A29

--cyclopropyl-- 657 A29

--cyclopropyl-- 658 A29

--cyclopropyl-- 659 A29

--cyclopropyl-- 660 A29

--cyclopropyl-- 661 A29

--cyclopropyl-- 662 A29

--cyclopropyl-- 663 A29

--cyclopropyl- 664 A29

--cyclopropyl-- 665 A29

--cyclopropyl-- 666 A29

--cyclopropyl-- 667 A29

--cyclopropyl-- 668 A29

--cyclopropyl-- 669 A29

--cyclopropyl-- 670 A29

--cyclopropyl-- 671 A29

--cyclopropyl-- 672 A29

--cyclopropyl-- 673 A29

--cyclopropyl-- 674 A29

--cyclopropyl-- 675 A29

--cyclopropyl-- 676 A29

--cyclopropyl-- 677 A29

--cyclopropyl-- 678 A29

--cyclopropyl-- 679 A29

--cyclopropyl-- 680 A29

--cyclopropyl-- 681 A29

--cyclopropyl-- 682 A29

--cyclopropyl-- 683 A29

--cyclopropyl-- 684 A29

--cyclopropyl-- 685 A29

--cyclopropyl-- 686 A29

--cyclopropyl-- 687 A29

--cyclopropyl-- 688 A29

--cyclopropyl-- 689 A29

--cyclopropyl-- 690 A29

--cyclopropyl-- 691 A29

--cyclopropyl-- 692 A29

--cyclopropyl-- 693 A29

--cyclopropyl-- 694 A29

--cyclopropyl- 695 A29

--cyclopropyl-- 696 A29

--cyclopropyl-- 697 A29

--cyclopropyl-- 698 A29

--cyclopropyl-- 699 A29

--cyclopropyl-- 700 A29

--cyclopropyl-- 701 A29

--cyclopropyl-- 702 A29

--cyclopropyl-- 703 A29

--cyclopropyl-- 704 A29

--cyclopropyl-- 705 A29

--cyclopropyl-- 706 A29

--cyclopropyl-- 707 A29

--cyclopropyl-- 708 A29

--cyclopropyl-- 709 A29

--cyclopropyl-- 710 A29

--cyclopropyl-- 711 A29

--cyclopropyl-- 712 A29

--cyclopropyl-- 713 A29

--cyclopropyl-- 714 A29

--cyclopropyl-- 715 A29

--cyclopropyl-- 716 A29

--cyclopropyl-- 717 A29

--cyclopropyl-- 718 A29

--cyclopropyl-- 719 A29

--cyclopropyl-- 720 A29

--cyclopropyl-- 721 A29

--cyclopropyl-- 722 A29

--cyclopropyl-- 723 A29

--cyclopropyl-- 724 A29

--cyclopropyl-- 725 A29

--cyclopropyl-- 726 A29

--cyclopropyl-- 727 A29

--cyclopropyl-- 728 A29

--cyclopropyl-- 729 A29

--cyclopropyl-- 730 A29

--cyclopropyl-- 731 A29

--cyclopropyl-- 732 A29

--cyclopropyl--

Dosage and Administration

The present disclosure includes pharmaceutical composition for treating a subject having a neurological disorder comprising a therapeutically effective amount of a compound of Formula (I), a derivative or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient, carrier or diluent.

The pharmaceutical compositions can be administered in a variety of dosage forms including, but not limited to, a solid dosage form or in a liquid dosage form, an oral dosage form, a parenteral dosage form, an intranasal dosage form, a suppository, a lozenge, a troche, buccal, a controlled release dosage form, a pulsed release dosage form, an immediate release dosage form, an intravenous solution, a suspension or combinations thereof. The dosage can be an oral dosage form that is a controlled release dosage form. The oral dosage form can be a tablet or a caplet. The compounds can be administered, for example, by oral or parenteral routes, including intravenous, intramuscular, intraperitoneal, subcutaneous, transdermal, airway (aerosol), rectal, vaginal and topical (including buccal and sublingual) administration. In one embodiment, the compounds or pharmaceutical compositions comprising the compounds are delivered to a desired site, such as the brain, by continuous injection via a shunt.

In another embodiment, the compound can be administered parenterally, such as intravenous (IV) administration. The formulations for administration will commonly comprise a solution of the compound of the Formula (I) dissolved in a pharmaceutically acceptable carrier. Among the acceptable vehicles and solvents that can be employed are water and Ringer's solution, an isotonic sodium chloride. In addition, sterile fixed oils can conventionally be employed as a solvent or suspending medium. For this purpose any bland fixed oil can be employed including synthetic mono- or diglycerides. In addition, fatty acids such as oleic acid can likewise be used in the preparation of injectables. These solutions are sterile and generally free of undesirable matter. These formulations may be sterilized by conventional, well known sterilization techniques. The formulations may contain pharmaceutically acceptable auxiliary substances as required to approximate physiological conditions such as pH adjusting and buffering agents, toxicity adjusting agents, e.g., sodium acetate, sodium chloride, potassium chloride, calcium chloride, sodium lactate and the like. The concentration of compound of Formula (I) in these formulations can vary widely, and will be selected primarily based on fluid volumes, viscosities, body weight, and the like, in accordance with the particular mode of administration selected and the patient's needs. For IV administration, the formulation can be a sterile injectable preparation, such as a sterile injectable aqueous or oleaginous suspension. This suspension can be formulated according to the known art using those suitable dispersing or wetting agents and suspending agents. The sterile injectable preparation can also be a sterile injectable solution or suspension in a nontoxic parenterally-acceptable diluent or solvent, such as a solution of 1,3-butanediol.

In one embodiment, a compound of Formula (I) can be administered by introduction into the central nervous system of the subject, e.g., into the cerbrospinal fluid of the subject. The formulations for administration will commonly comprise a solution of the compound of Formula (I) dissolved in a pharmaceutically acceptable carrier. In certain aspects, the compound of Formula (I) is introduced intrathecally, e.g., into a cerebral ventricle, the lumbar area, or the cisterna magna. In another aspect, the compound of Formula (I) is introduced intraocularly, to thereby contact retinal ganglion cells.

The pharmaceutically acceptable formulations can easily be suspended in aqueous vehicles and introduced through conventional hypodermic needles or using infusion pumps. Prior to introduction, the formulations can be sterilized with, preferably, gamma radiation or electron beam sterilization.

In one embodiment, the pharmaceutical composition comprising a compound of Formula (I) is administered into a subject intrathecally. As used herein, the term “intrathecal administration” is intended to include delivering a pharmaceutical composition comprising a compound of Formula (I) directly into the cerebrospinal fluid of a subject, by techniques including lateral cerebroventricular injection through a burrhole or cisternal or lumbar puncture or the like (described in Lazorthes et al. Advances in Drug Delivery Systems and Applications in Neurosurgery, 143-192 and Omaya et al., Cancer Drug Delivery, 1: 169-179, the contents of which are incorporated herein by reference). The term “lumbar region” is intended to include the area between the third and fourth lumbar (lower back) vertebrae. The term “cisterna magna” is intended to include the area where the skull ends and the spinal cord begins at the back of the head. The term “cerebral ventricle” is intended to include the cavities in the brain that are continuous with the central canal of the spinal cord. Administration of a compound of Formula (I) to any of the above mentioned sites can be achieved by direct injection of the pharmaceutical composition comprising the compound of Formula (I) or by the use of infusion pumps. For injection, the pharmaceutical compositions can be formulated in liquid solutions, preferably in physiologically compatible buffers such as Hank's solution or Ringer's solution. In addition, the pharmaceutical compositions may be formulated in solid form and re-dissolved or suspended immediately prior to use. Lyophilized forms are also included. The injection can be, for example, in the form of a bolus injection or continuous infusion (e.g., using infusion pumps) of pharmaceutical composition.

In one embodiment, the pharmaceutical composition comprising a compound of Formula (I) is administered by lateral cerebro ventricular injection into the brain of a subject. The injection can be made, for example, through a burr hole made in the subject's skull. In another embodiment, the encapsulated therapeutic agent is administered through a surgically inserted shunt into the cerebral ventricle of a subject. For example, the injection can be made into the lateral ventricles, which are larger, even though injection into the third and fourth smaller ventricles can also be made.

In yet another embodiment, the pharmaceutical composition is administered by injection into the cisterna magna, or lumbar area of a subject.

For oral administration, the compounds will generally be provided in unit dosage forms of a tablet, pill, dragee, lozenge or capsule; as a powder or granules; or as an aqueous solution, suspension, liquid, gels, syrup, slurry, etc. suitable for ingestion by the patient. Tablets for oral use may include the active ingredients mixed with pharmaceutically acceptable excipients such as inert diluents, disintegrating agents, binding agents, lubricating agents, sweetening agents, flavoring agents, coloring agents and preservatives. Suitable inert diluents include sodium and calcium carbonate, sodium and calcium phosphate, and lactose, while corn starch and alginic acid are suitable disintegrating agents. Binding agents may include starch and gelatin, while the lubricating agent, if present, will generally be magnesium stearate, stearic acid or talc. If desired, the tablets may be coated with a material such as glyceryl monostearate or glyceryl distearate, to delay absorption in the gastrointestinal tract.

Pharmaceutical preparations for oral use can be obtained through combination of a compound of Formula (I) with a solid excipient, optionally grinding a resulting mixture, and processing the mixture of granules, after adding suitable additional compounds, if desired, to obtain tablets or dragee cores. Suitable solid excipients in addition to those previously mentioned are carbohydrate or protein fillers that include, but are not limited to, sugars, including lactose, sucrose, mannitol, or sorbitol; starch from corn, wheat, rice, potato, or other plants; cellulose such as methyl cellulose, hydroxypropylmethyl-cellulose or sodium carboxymethylcellulose; and gums including arabic and tragacanth; as well as proteins such as gelatin and collagen. If desired, disintegrating or solubilizing agents may be added, such as the cross-linked polyvinyl pyrrolidone, agar, alginic acid, or a salt thereof, such as sodium alginate.

Capsules for oral use include hard gelatin capsules in which the active ingredient is mixed with a solid diluent, and soft gelatin capsules wherein the active ingredients is mixed with water or an oil such as peanut oil, liquid paraffin or olive oil.

Dragee cores are provided with suitable coatings. For this purpose, concentrated sugar solutions may be used, which may optionally contain gum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethylene glycol, and/or titanium dioxide, lacquer solutions, and suitable organic solvents or solvent mixtures. Dyestuffs or pigments may be added to the tablets or dragee coatings for identification or to characterize different combinations of active compound doses.

For transmucosal administration (e.g., buccal, rectal, nasal, ocular, etc.), penetrants appropriate to the barrier to be permeated are used in the formulation. Such penetrants are generally known in the art.

Formulations for rectal administration may be presented as a suppository with a suitable base comprising for example cocoa butter or a salicylate. Formulations suitable for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams or spray formulations containing in addition to the active ingredient such carriers as are known in the art to be appropriate. For intramuscular, intraperitoneal, subcutaneous and intravenous use, the compounds will generally be provided in sterile aqueous solutions or suspensions, buffered to an appropriate pH and isotonicity. Suitable aqueous vehicles include Ringer's solution and isotonic sodium chloride. Aqueous suspensions may include suspending agents such as cellulose derivatives, sodium alginate, polyvinyl-pyrrolidone and gum tragacanth, and a wetting agent such as lecithin. Suitable preservatives for aqueous suspensions include ethyl and n-propyl p-hydroxybenzoate.

The suppositories for rectal administration of the drug can be prepared by mixing the drug with a suitable non-irritating excipient which is solid at ordinary temperatures but liquid at the rectal temperatures and will therefore melt in the rectum to release the drug. Such materials are cocoa butter and polyethylene glycols.

The compounds can be delivered transdermally, by a topical route, formulated as applicator sticks, solutions, suspensions, emulsions, gels, creams, ointments, pastes, jellies, paints, powders, or aerosols.

The compounds may also be presented as aqueous or liposome formulations. Aqueous suspensions can contain a compound of Formula (I) in admixture with excipients suitable for the manufacture of aqueous suspensions. Such excipients include a suspending agent, such as sodium carboxymethylcellulose, methylcellulose, hydroxypropylmethylcellulose, sodium alginate, polyvinylpyrrolidone, gum tragacanth and gum acacia, and dispersing or wetting agents such as a naturally occurring phosphatide (e.g., lecithin), a condensation product of an alkylene oxide with a fatty acid (e.g., polyoxyethylene stearate), a condensation product of ethylene oxide with a long chain aliphatic alcohol (e.g., heptadecaethylene oxycetanol), a condensation product of ethylene oxide with a partial ester derived from a fatty acid and a hexitol (e.g., polyoxyethylene sorbitol mono-oleate), or a condensation product of ethylene oxide with a partial ester derived from fatty acid and a hexitol anhydride (e.g., polyoxyethylene sorbitan monooleate). The aqueous suspension can also contain one or more preservatives such as ethyl or n-propyl p-hydroxybenzoate, one or more coloring agents, one or more flavoring agents and one or more sweetening agents, such as sucrose, aspartame or saccharin. Formulations can be adjusted for osmolarity.

Oil suspensions can be formulated by suspending a compound of Formula (I) in a vegetable oil, such as arachis oil, olive oil, sesame oil or coconut oil, or in a mineral oil such as liquid paraffin; or a mixture of these. The oil suspensions can contain a thickening agent, such as beeswax, hard paraffin or cetyl alcohol. Sweetening agents can be added to provide a palatable oral preparation, such as glycerol, sorbitol or sucrose. These formulations can be preserved by the addition of an antioxidant such as ascorbic acid. As an example of an injectable oil vehicle, see Minto, J. Pharmacol. Exp. Ther. 281:93-102, 1997. The pharmaceutical formulations can also be in the form of oil-in-water emulsions. The oily phase can be a vegetable oil or a mineral oil, described above, or a mixture of these. Suitable emulsifying agents include naturally-occurring gums, such as gum acacia and gum tragacanth, naturally occurring phosphatides, such as soybean lecithin, esters or partial esters derived from fatty acids and hexitol anhydrides, such as sorbitan mono-oleate, and condensation products of these partial esters with ethylene oxide, such as polyoxyethylene sorbitan mono-oleate. The emulsion can also contain sweetening agents and flavoring agents, as in the formulation of syrups and elixirs. Such formulations can also contain a demulcent, a preservative, or a coloring agent.

In addition to the formulations described previously, the compounds may also be formulated as a depot preparation. Such long acting formulations may be administered by implantation or transcutaneous delivery (e.g., subcutaneously or intramuscularly), intramuscular injection or a transdermal patch. Thus, for example, the compounds may be formulated with suitable polymeric or hydrophobic materials (e.g., as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, for example, as a sparingly soluble salt.

The pharmaceutical compositions also may comprise suitable solid or gel phase carriers or excipients. Examples of such carriers or excipients include but are not limited to calcium carbonate, calcium phosphate, various sugars, starches, cellulose derivatives, gelatin, and polymers such as polyethylene glycols.

For administration by inhalation, the compounds are conveniently delivered in the form of an aerosol spray presentation from pressurized packs or a nebulizer, with the use of a suitable propellant, e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In the case of a pressurized aerosol the dosage unit may be determined by providing a valve to deliver a metered amount. Capsules and cartridges of e.g., gelatin for use in an inhaler or insufflator may be formulated containing a powder mix of the compound and a suitable powder base such as lactose or starch.

In general a suitable dose will be in the range of 0.01 to 100 mg per kilogram body weight of the recipient per day, preferably in the range of 0.1 to 10 mg per kilogram body weight per day. The desired dose is preferably presented once daily, but may be dosed as two, three, four, five, six or more sub-doses administered at appropriate intervals throughout the day.

The compounds can be administered as the sole active agent, or in combination with other known therapeutics to be beneficial in the treatment of neurological disorders. In any event, the administering physician can provide a method of treatment that is prophylactic or therapeutic by adjusting the amount and timing of drug administration on the basis of observations of one or more symptoms (e.g., motor or cognitive function as measured by standard clinical scales or assessments) of the disorder being treated.

Details on techniques for formulation and administration are well described in the scientific and patent literature, see, e.g., the latest edition of Remington's Pharmaceutical Sciences, Maack Publishing Co, Easton Pa. After a pharmaceutical composition has been formulated in an acceptable carrier, it can be placed in an appropriate container and labeled for treatment of an indicated condition. For administration of the compounds of Formula (I), such labeling would include, e.g., instructions concerning the amount, frequency and method of administration.

Biological Examples In Vivo Methods

Subjects:

Male C57BL/6J mice (Charles River; 20-25 g) were used for all assays except prepulse inhibition (PPI) which used male DBA/2N mice (Charles River, 20-25 g). For all studies, animals were housed five/cage on a 12-h light/dark cycle with food and water available ad libitum.

Conditioned Avoidance Responding:

Testing was performed in commercially available avoidance boxes (Kinder Scientific, Poway Calif.). The boxes were divided into two compartments separated by an archway. Each side of the chamber has electronic grid flooring that is equipped to administer footshocks and an overhead light. Training consisted of repeated pairings of the light (conditioned stimulus) followed by a shock (unconditioned stimulus). For each trial the light was presented for 5 sec followed by a 0.5 mA shock that would terminate if the mouse crossed to the other chamber or after 10 seconds. The intertrial interval was set to 20 seconds. Each training and test session consisted a four min habituation period followed by 30 trials. The number of avoidances (mouse crossed to other side during presentation of the light,), escapes (mouse crossed to the other side during presentation of the shock) and failures (mouse did not cross during the entire trial period) were recorded by a computer. For study inclusion an animal had to reach a criterion of at least 80% avoidances for two consecutive test sessions.

PPI:

Mice were individually placed into the test chambers (StartleMonitor, Kinder Scientific, Poway Calif.). The animals were given a five min acclimation period to the test chambers with the background noise level set to 65 decibel (dB) which remained for the entire test session. Following acclimation, four successive trials 120 dB pulse for 40 msec were presented, however these trials were not included in data analysis. The mice were then subjected to five different types of trials in random order: pulse alone (120 dB for 40 msec), no stimulus and three different prepulse+pulse trials with the prepulse set at 67, 69 or 74 dB for 20 msec followed a 100 msec later by a 120 dB pulse for 40 msec. Each animal received 12 trials for each condition for a total of 60 trials with an average intertrial interval of 15 sec. Percent PPI was calculated according to the following formula: (1−(startle response to prepulse+pulse)/startle response to pulse alone))×100.

MK-801-Induced Hyperactivity:

After a 30 min acclimatation to the test room mice were individually placed into test cages for a 30 min habituation period. Following habituation to test cages, baseline activity was recorded for 60 min. Mice were then briefly removed and administered test compound and placed immediately back into the test cage. At 5 min prior to test time mice were again briefly removed from test cages and administered MK-801 (0.3 mg/kg, i.p. in 0.9% saline) and then immediately placed back into test cages and activity level recorded 1 hour. Activity level was measured as distance travelled in centimeters (Ethovision tracking software, Noldus Inc. Wageningen, Netherlands).

Catalepsy:

Mice were placed on a wire mesh screen set at a 60 degree angle with their heads facing upwards and the latency to move or break stance was recorded. Animals were given three trials per time point with a 30 sec cut-off per trial.

Data Analysis:

A one-way or two-way ANOVA was used to evaluate overall differences between treatments and a Tukey's post-hoc test or Student's t-test was used to evaluate differences between treatment groups for the one-way ANOVA and a Bonferroni test was used for the two-way ANOVA. The criterion for statistical significance was set to p<0.05.

In Vitro Methods

hPDE10A1 Enzyme Activity:

50 μl samples of serially diluted Human PDE10A1 enzyme were incubated with 50 μl of [³H]-cAMP for 20 minutes (at 37° C.). Reactions were carried out in Greiner 96 deep well 1 ml master-block. The enzyme was diluted in 20 mM Tris HCl pH7.4 and [³H]-cAMP was diluted in 10 mM MgCl₂, 40 mM Tris.HCl pH 7.4. The reaction was terminated by denaturing the PDE enzyme (at 70° C.) after which [³H]-5′-AMP was converted to [³H]-adenosine by adding 25 μl snake venom nucleotidase and incubating for 10 minutes (at 37° C.). Adenosine, being neutral, was separated from charged cAMP or AMP by the addition of 200 μl Dowex resin. Samples were shaken for 20 minutes then centrifuged for 3 minutes at 2,500 r.p.m. 50 μl of supernatant was removed and added to 200 μl of MicroScint-20 in white plates (Greiner 96-well Optiplate) and shaken for 30 minutes before reading on Perkin Elmer TopCount Scintillation Counter.

hPDE10A1 Enzyme Inhibition:

To check inhibition profile 11 μl of serially diluted inhibitor was added to 50 μl of [³H]-cAMP and 50 ul of diluted Human PDE10A1 and assay was carried out as in the enzyme activity assay. Data was analysed using Prism software (GraphPad Inc). Representative compounds of this disclosure are shown in the table below. A compound with the value “A” had an IC₅₀ value less than or equal to 10 nM. A compound with the value “B” had an IC₅₀ value greater than 10 nM and less than 50 nM:

hPDE10A1 Name IC₅₀ Band 4-(4-((3,5-dimethylpyridin-2-yl)methoxy)phenyl)-5- A (4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one 4-(4-(imidazo[1,2-a]pyridin-2-ylmethoxy)phenyl)- A 5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one 4-(4-(imidazo[1,2-b]pyridazin-6-ylmethoxy)phenyl)- B 5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one 4-(4-((6-chloroimidazo[1,2-b]pyridazin-2- B yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2- dimethylfuran-3(2H)-one 4-(4-(imidazo[1,2-b]pyridazin-2-ylmethoxy)phenyl)- A 5-(4-methoxyphenyl)-2,2-dimethylfuran-3(2H)-one 4-(3-(4-(imidazo[1,2-a]pyridin-2-ylmethoxy)phenyl)- A 5,5-dimethyl-4-oxo-4,5-dihydrofuran-2-yl)benzonitrile 4-(4-((3-chloroimidazo[1,2-a]pyridin-2- A yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2- dimethylfuran-3(2H)-one 5-(4-methoxyphenyl)-2,2-dimethyl-4-(4-((5-methylpyridin- A 2-yl)methoxy)phenyl)furan-3(2H)-one 4-(5,5-dimethyl-3-(4-((5-methylpyridin-2- A yl)methoxy)phenyl)-4-oxo-4,5-dihydrofuran- 2-yl)benzonitrile 4-(4-((6-chloroimidazo[1,2-a]pyridin-2- A yl)methoxy)phenyl)-5-(4-methoxyphenyl)-2,2- dimethylfuran-3(2H)-one 5-(4-methoxyphenyl)-2,2-dimethyl-4-(4-((3- B methylimidazo[1,2-a]pyridin-2- yl)methoxy)phenyl)furan-3(2H)-one 5-(4-methoxyphenyl)-2,2-dimethyl-4-(4-((5- A methylimidazo[1,2-a]pyridin-2- yl)methoxy)phenyl)furan-3(2H)-one 

What is claimed is:
 1. A compound of Formula (I) and pharmaceutically acceptable salts thereof,

wherein: HET is selected from A29 and A31

wherein the left most radical is connected to the X group in Formula (I); X is selected from optionally substituted aryl and optionally substituted heteroaryl, wherein the substituents are selected from C₁-C₄ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkyloxy, C₁-C₄ alkoxy, CF₃, carboxy, alkoxyalkyl, C₁-C₄ cycloalkylalkoxy, amino, alkylamino, dialkylamino, amido, alkylamido, dialkylamido, thioalkyl, halogen, cyano, alkylsulfonyl and nitro; and Z is selected from pyridin-2-yl, imidazo[1,2-a]pyridin-2-yl, imidazo[1,2-b]pyridazin-2-yl, and imidazo[1,2-b]pyridazin-6-yl, each of which can be optionally substituted, wherein the substituents are selected from C₁-C₄ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkyloxy, C₁-C₄ alkoxy, CF₃, carboxy, alkoxyalkyl, C₁-C₄ cycloalkylalkoxy, amino, alkylamino, dialkylamino, amido, alkylamido, dialkylamido, thioalkyl, halogen, cyano, alkylsulfonyl and nitro; and each R₂ is independently selected from optionally fluoro substituted C₁-C₄ alkyl or two R₂ groups taken together with the carbon to which they are attached form a 3 membered cycloalkyl ring. 2-35. (canceled)
 36. A method for making 4-(4-hydroxyphenyl)-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one or a salt thereof, the method comprising using Suzuki coupling to obtain 4-(4-hydroxyphenyl)-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one or a salt thereof from 4-bromo-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one.
 37. The method of claim 36, conducted in a polar solvent mixture.
 38. The method of claim 37, wherein the polar solvent mixture comprises water.
 39. The method of claim 36, conducted in the presence of a catalyst.
 40. The method of claim 39, wherein the catalyst is a palladium(0) or palladium(II) catalyst.
 41. The method of claim 36 conducted in the presence of a base.
 42. The method of claim 41, wherein the base is selected from the group consisting of potassium carbonate, sodium carbonate and cesium carbonate.
 43. The method of claim 36, further comprising isolating 4-(4-hydroxyphenyl)-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one or a salt thereof.
 44. A method for making 4-(4-((6-chloroimidazo[1,2-b]pyridazin-2-yl)methoxy)phenyl)-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one or a salt thereof, the method comprising contacting 4-(4-hydroxyphenyl)-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one with a compound of formula

to provide 4-(4-((6-chloroimidazo[1,2-b]pyridazin-2-yl)methoxy)phenyl)-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one or a salt thereof.
 45. The method of claim 44, conducted in a polar solvent.
 46. The method of claim 45, wherein the polar solvent is CH₃CN or DMF.
 47. The method of claim 44 conducted in the presence of a base.
 48. The method of claim 47, wherein the base is selected from the group consisting of potassium carbonate, sodium carbonate and cesium carbonate.
 49. The method of claim 44, further comprising isolating 4-(4-((6-chloroimidazo[1,2-b]pyridazin-2-yl)methoxy)phenyl)-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one or a salt thereof.
 50. A method for making 4-(4-(imidazo[1,2-b]pyridazin-2-ylmethoxy)phenyl)-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one or a salt thereof, the method comprising reducing 4-(4-((6-chloroimidazo[1,2-b]pyridazin-2-yl)methoxy)phenyl)-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one to provide 4-(4-(imidazo[1,2-b]pyridazin-2-ylmethoxy)phenyl)-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one or a salt thereof.
 51. The method of claim 50, conducted in the presence of a catalyst.
 52. The method of claim 51, wherein the catalyst is a palladium(0) or palladium(II) catalyst.
 53. The method of claim 50, conducted in the presence of hydrogen.
 54. The method of claim 50, further comprising isolating 4-(4-(imidazo[1,2-b]pyridazin-2-ylmethoxy)phenyl)-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one or a salt thereof. 